Composite Pipes and Method Making Same

ABSTRACT

Reinforced composite pipes and methods for making the same, generally employ at least one polymeric reinforcement phase, typically provided as an intermediate form  214 . The intermediate form is typically applied over a core pipe  216 , and may be consolidated. An optional jacket may be employed.

CLAIM OF PRIORITY

The present application claims priority to, and the benefit of thefiling date of, U.S. Provisional Application Nos. 60/621,463 filed onOct. 22, 2004 (Attorney Docket No. 63863; 1062-041P1); 60/717,965 filedon Sep. 16, 2005 (Attorney Docket No. 63863B; 1062-041P2); 60/718,025filed on Sep. 16, 2005 (Attorney Docket No. 64371; 1062-051P1); and60/725,399 filed on Oct. 11, 2005 (Attorney Docket No. 63863C;1062-041P3), (Express Mail No. EV789808245US), all of which areincorporated by reference.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to concurrently filed, commonlyowned, copending application entitled Apparatus and Process forManufacturing Shaped Plastic Reinforced Composite Articles (AttorneyDocket No. 64371A; 1062-051WO); Improved Polyolefinic Materials ForPlastic Composites (Attorney Docket No. 63863D; 1062-41WO1); PlasticComposite Articles and Methods of Making Same (Attorney Docket No.63863E; 1062-41WO2); and Improved Microlayer Structures and Methods(Attorney Docket No. 63863F; 1062-41WO3); all of which are incorporatedby reference.

TECHNICAL FIELD

The present invention pertains generally to pipes, and more specificallyto composite pipes that employ at least one polymeric reinforcementphase.

BACKGROUND OF INVENTION

The past several decades have seen considerable advancement inengineering materials through the development of improved compositematerials. Composites allow designers to combine advantageous featuresof multiple component materials to arrive at a material that typicallyhas one or more different properties than the component materialsindividually.

One area that has seen particularly rapid advancement is the area ofreinforced plastics. For example, it is popular to improve properties ofa plastic by incorporating an inorganic reinforcement phase, such as theemployment of a fiber that is made of glass, carbon, metal or anotherinorganic material. In a number of instances, a form is provided thatincorporates the inorganic reinforcement material, and is impregnated orotherwise intermixed with a thermoplastic or thermoset plastic matrix.One particular example that has seen increased popularity in recentyears is a Glass Mat Thermoplastic (GMT) composite, which ordinarilyemploys a glass mat reinforcement phase that is impregnated with athermoplastic such as polypropylene. The difference of material typesbetween the glass and the thermoplastic matrix tends to complicate anyreclamation or recycling efforts with these GMT materials.

In recent years, the plastics industry also has seen experimentation inthe development of thermoplastic “fabrics” that employ a weave of one ormore thermoplastic fibers, with or without a glass fiber as well.Typically, these materials are offered in a woven and consolidated form,namely, upon weaving the fibres, they are heated to melt at least aportion of their outer surface. Upon solidification, adjoining fibersare solidified together.

To date, efforts to provide a suitable thermoplastic reinforcement formthat can readily be processed to form a resulting article. It has beenobserved, for example, that the step of consolidation (wherein thefibers or other units of the reinforcement form are heated to fusetogether), requires at least a first heat history, and the step offorming the resulting shaped article requires at least a second heathistory. With each additional heat history, the opportunity formorphology change is increased, with the attendant loss of mechanicalproperties.

One particular application of plastic reinforced composites is in themanufacture of pipes. Cabrera, “Recycleable All-PolypropyleneComposites: Concept, Properties and Manufacturing”, TechnischeUniversiteit Eindhoven (2004)(ISBN 90-386-2676-2), incorporated byreference herein, discloses an example of one approach to making a pipewith a winding. See also, UK Patent No. 2279232, incorporated byreference. It would be attractive to manufacture a variety of pipeshaving a wide spectrum of properties.

SUMMARY OF THE INVENTION

By way of summary, the teachings contemplate a method for making acomposite pipe that includes the steps of providing a core pipe;covering the core pipe (e.g., made of a polymer) with an intermediateform that includes at least one winding of a thermoplastic elongatedmember, wherein the elongated member comprises a first thermoplasticmaterial and a second thermoplastic material; consolidating theintermediate form; and optionally applying a jacket over at least aportion of the intermediate form and the core pipe for protecting thecore pipe with the intermediate form.

The intermediate form typically includes a plurality of elongated memberlayers, with at least one of the layers including an elongated memberstretched to at least about 5× (and possibly as high as 15× or higher).The elongated members may comprise a multilayer coextruded tape and theconsolidating step, particularly where a propylene-based polyolefin isemployed in an elongated member, includes maintaining the intermediateform at a temperature of at least about 150° C. for at least about oneminute, after the core pipe is covered with the intermediate form. Aplurality of layers of windings may be employed.

If employed, the protective jacket typically includes a polymer and thejacket has a pressure rating (per ISO 9080) of greater than about PE 80.Resulting pipes will have a hoop stress performance for withstanding apressure of 7 MPa at 80° C. for up to 250 hours. Any jacket applied, atleast one of the thermoplastic materials of the intermediate form, orboth may include a non-migratory process aid or surface modifier agentas taught herein. In one approach, at least one of the firstthermoplastic material and the second thermoplastic material includesethylene. In a specific aspect, the elongated member is made from (i) afirst thermoplastic material that comprises a propylene-ethylenecopolymer, (ii) a second thermoplastic material that comprises anisotactic polypropylene homopolymer (e.g., having a crystallinity of atleast about 30%, and an isotactic pentad/triad ratio of greater thanabout 70%); or a combination of (i) and (ii). A plurality of microlayersmay be employed for the elongated member.

In one approach, the step of consolidating the intermediate form occursprior to application of the jacket over at least a portion of theintermediate form and the core pipe. In another approach, the step ofconsolidating occurs from heat realized during the step of applying thejacket.

DESCRIPTION OF THE DRAWINGS

FIG. 1A and FIG. 1B illustrate examples of cross sections of possibleelongated members of the present teachings.

FIG. 2A and FIG. 2B illustrate respectively an example of anunconsolidated and consolidated intermediate form in accordance with thepresent teachings.

FIG. 3 is a perspective view of an illustrative shaped intermediate formin accordance with the present teachings.

FIGS. 4A-4G illustrate pipe structures in accordance with the presentteachings.

FIGS. 5A and 5B illustrate exemplary comparative data obtainable withthe present teachings.

FIGS. 6A and 6B illustrate exemplary data obtainable with the presentteachings.

DETAILED DESCRIPTION

In connection with the manufacture of composite pipes according to thepresent teachings, one particular aspect is directed toward making anintermediate form and include steps of a) providing at least oneelongated member of a first thermoplastic material and having a surfaceportion capable of melting prior to the melting of an adjoining orinternal portion (such as an internal oriented portion); and b)processing the elongated member into an intermediate form that mayinclude a plurality of repeating structural units that are generallyfree to move relative to each other, wherein the form is capable ofbeing processed to form a substantially smooth, ruck-free shapedfinished article. In general, though not required in every instance(such as with the microlayer teachings herein) elongated members willcomprise an oriented polyolefin, and particularly one that can beprocessed according to the present teachings with substantial retentionof its initial morphology.

Process steps herein may also include steps of consolidating and shapinga three-dimensional intermediate form (e.g., simultaneously in a singleoperation or consecutively in a plurality of operations) that includesat least one elongated member and a plurality of repeating structuralunits of a first thermoplastic material having a surface portion capableof melting prior to an adjoining portion (such as an adjoining orientedportion); placing the consolidated and shaped intermediate form into acavity of a tool; introducing a second thermoplastic material into thetool cavity; and ejecting from the tool cavity a reinforced compositepipe that includes the consolidated intermediate form and the secondthermoplastic material. It is also possible that partial consolidationis performed during the step of introducing the second thermoplasticmaterial into the tool cavity. This illustrative aspect, of course, maybe practiced in combination with, or separate from the above firstillustrative aspect. Thus, it is possible that a single manufacturer canmake the intermediate form and the resulting article, or differentmanufacturers may make each (e.g., a materials supplier would supply theintermediate form to an article manufacturer). Further, it is possiblethat the above steps may be practiced in the absence of consolidation ofthe form prior to introduction of the second thermoplastic material intothe tool cavity. Typical articles prepared according to the teachingsherein advantageously will exhibit excellent impact and relatedcharacteristics (particularly due to the ability, through the use ofunique selections or combinations of materials, and/or processingconditions), as a result of a high degree of retained morphology in theelongated member portion of the article.

As indicated various aspects of the present invention are predicatedupon the discovery of unique combinations of materials, processingsteps, or both, that result in a relatively high degree of retainedmorphology in the elongated member materials (as compared with itsinitial morphology upon its initial stretch and prior to processing toform a composite article). In this manner, the teachings hereinadvantageously allow for the beneficial preservation of properties suchas impact properties in the resulting composite articles.

As will be seen, the teachings herein will address novel combinations ofmaterials that find utility in the field of composites, particularly asrespecting elongated members that can be consolidated and optionallyshaped and processed for forming a composite pipe.

As will be observed from the teachings herein, various of the aspectsare illustrated in the context of polyolefinic materials, though theteachings are not to be so limited. Among the specific advancementsoffered by the present invention is the recognition of specificpolyolefinic material combinations that have unique applicability in thecomposites field. In particular, one aspect of the present invention ispremised upon the recognition for use as multiple layer elongated memberof a propylene-based (e.g., a propylene-ethylene copolymer, apropylene-α-olefin copolymer, mixtures thereof or otherwise) copolymerthat has a melting point that is below an adjoining polypropylene layer,and specifically an oriented polypropylene layer. Upon processing toform articles as taught herein, the resulting materials (especially theoriented polypropylene layer) exhibits a degree of retained morphologyfrom its initial drawn state, heretofore not attainable usingconventional materials. Accordingly, aspects of the present inventionare premised upon the use of a propylene-ethylene copolymer that has anethylene content of about 3 to 25 wt. % (e.g., 5 to 15 wt. %), a meltingrange of about 50 to 135° C., and a flexural modulus of about 8 to about325 Mpa or higher (e.g., at least about 375 MPa), and a secondthermoplastic material that includes a polyolefin, such as apropylene-based polymer. Such propylene-ethylene copolymer may have aShore A Hardness of from about 40 to 90, a molecular weight distributionof about 1.5 to about 4, and a melt flow rate of at least about 0.3 g/10min, or any combination thereof.

One example of a propylene-based polymer that may be employed generallywill be isotactic and relatively stiff. For example, it may be apolypropylene homopolymer that has a 1% secant flexural modulus ofgreater than about 1000 MPA, (and more specifically greater than about2000 Mpa (e.g., about 2500 Mpa or higher)), an isotactic pentad/triadratio of greater than about 70% (e.g., greater than about 85%) or both.Moreover, such a polypropylene typically will have a peak meltingtemperature of greater than about 160° C. (e.g., greater than about 165°C.), a crystallinity of at least about 30% (more specifically at leastabout 50% or even 70%) or both.

The teachings herein are also premised upon the recognition that, foruse with the above polymers, or with other polymers taught herein,advantageous results are possible by the use of an optionalnon-migratory process aid or surface modifier agent in an amount lessthan about 10% by weight of the material of the elongated member. By wayof example, the non-migratory process aid or surface modifier agent mayinclude an agent selected from silicones (e.g., a high molecular weightsilicone, such as an alkyl siloxane like dimethylsiloxane), polyolefins,halogenated polymers, or any combination thereof.

In regard to novel combinations of materials, the teachings hereinidentify an unexpected approach to the fabrication of composites by theuse therein of a geophysical textile material (e.g., a polyolefingeophysical textile). For example, one such method envisions steps ofproviding an intermediate form that includes a geophysical textile, andovermolding or otherwise processing the intermediate form to form a pipestructure. Optionally, the above non-migratory process aid or surfacemodifier agent may be employed.

The teachings herein also illustrate that the present invention isdirected to embodiments that feature at least 4 stacked layers that eachinclude a polymer, each layer having a thickness less than about 50microns (an more typically considerably thinner, e.g., possibly eventhinner than about 5 microns), and each layer differing relative to itsadjoining layer in at least one characteristic selected fromcomposition, degree of crystallization, molecular orientation, molecularweight, melt rate, peak melting temperature, glass transition peak,temperature of crystallization, seal initiation temperature, softeningpoint, molecular weight distribution or any combination thereof.

As will be seen, without limitation, aspects of the present inventionalso pertain to articles produced with the materials described herein,further specific methods of making such articles, methods of using sucharticles, in addition to characteristics of the materials themselves andtheir processed forms.

Elongated Members and Intermediate Forms

Turning first to the intermediate forms of the present invention, ingeneral, these forms will include at least one elongated member with acomposition that includes at least one thermoplastic material. By“elongated member”, it is generally meant a member that has one of itsdimensions (e.g., length) that is longer than at least one otherdimension (e.g., width, height, thickness, or diameter), particularly,the length of an elongated member here in substantially greater (e.g.,by a factor of at least about 10 or higher) than the width or height.Accordingly, elongated members herein could include, but are notnecessarily limited to a member selected from fibres, rods, cords,yarns, tapes, filaments, straps or any combination thereof. As can beappreciated from the above, in a number of aspects, films may also becontemplated as within the meaning of “elongated members”. Small scalemembers may also be possible, such as whiskers or platelets. Though“elongated member” is regarded broadly herein, it should be recognizedthat particularly preferred forms of the elongated member specificallywill include one or more of yarns, tapes, fibres and filaments. A highlypreferred elongated member is in the form of a tape.

In addition, it should be appreciated that elongated members of thepresent invention typically will have been processed for achieving aninitial morphology, and specifically an initial orientation state (e.g.,it is monoaxially stretched, biaxially stretched, or otherwisestretched, such as in accordance with the proportions specified herein).Among the many unique advantages obtainable using the subject matterdisclosed herein is the ability upon conclusion of processing, andespecially in finished articles, to realize a substantial preservationof the initial morphology within the elongated member. Accordingly, forexample, upon processing, molecular orientation of the elongated memberis substantially preserved from its initial state (e.g., at least about50% and more preferably 75% of the initial orientation of the elongatedmember remains).

The dimensions of the elongated member typically could be such that itenables the member to be handled manually. More particularly, however,the elongated member will be dimensioned so that it is capable of beingmachine-handled for processing it into the intermediate form. Forexample, one specific illustration of the present invention envisions anelongated member, such as a yarn, tape, fiber or filament, that has athickness, width or diameter no larger than about 5 cm, morespecifically no larger than about 1 cm, still more specifically nolarger than about 0.5 cm, and even more specifically no larger thanabout 1 mm. For example, one approach is to employ an elongated membersuch as a yarn, tape, fiber or filament that has a width of less than 5mm, and a thickness of less than 1 mm and more specifically less than0.5 mm (e.g., about 0.01 to 0.25 mm). Of course, it is possible that anintermediate form may include a plurality of elongated members, eachbeing of different thickness, width or both. For example, the warp andweft elongated members of a woven form may respectively vary inthickness, width or both. Further, where films are employed as anelongated member herein, they may be substantially larger (e.g.,possibly as wide as at least about 5 meters, and at least about 10, 20,or even 40 meters long).

Typical elongated members will be continuous in profile. However, it ispossible that at least partially along the length of the elongatedmembers, the members could be fully densified, partially densified(e.g., foamed), perforated, corrugated, twisted, or any combinationthereof. The elongated member may have properties or othercharacteristics that differ along a dimension of the member.

As will be appreciated, the teachings herein are widespread and need notnecessarily be confined to the embodiments featured. For example, thepresent invention teaches a variety of different materials havingutility as elongated members, without regard to the particularapplication of such elongated members. However, especially in thecontext of teachings of polymeric reinforced composites, one or more ofthe elongated members herein are commonly assembled into an intermediateform, such as without limitation a woven, knit or other form in whichthere are a plurality of repeating structural units (e.g., the warps andwefts employ a plurality of elongated members). However, the repeatingunits may be as simple as the individual windings of a wound structure(such structure being possible through the use of a single elongatedmember.

Accordingly, after the formation of the elongated member, it isprocessed to make an intermediate form, such as one selected from awoven form, a winding form, a knit form, a braided form, a randomlydispersed form or any combination thereof. The form may also be wrappedor otherwise coated or covered. As referenced herein the intermediateform will typically include the plurality of repeating structural units.Examples of these structural units are illustrated in FIG. 2A. Forexample, an intermediate form 10 might include a plurality of repeatingstructural units 12 arranged to define a pattern 14, such as abasketweave of FIG. 2A, another plain weave, a twill weave (such as aherringbone, a tweed, a houndstooth, a plaid or other twill), a lace, asatin, or any combination thereof. Examples of particular weaves includeweaves that having a pattern warp elongated member running over and thenunder a weft elongated member in a warp/weft proportion ranging from 1/1to 14/2 (e.g., 2/1, 2/2, 3/1, or otherwise). Still more particularexamples of weaves include, without limitation, a 2/1 twill, a 2/2twill, a crowfoot satin, a 2/2 basketweave, a 5H satin, a 8-H satin, orotherwise. Thus, as can be seen, individual structural units of the formmay be disposed in any of a number of possible configurations relativeto each other. For example, as in FIGS. 2A and 2B, overlapping units maybe generally perpendicular to each other. However, other angles of weavemay also be employed as desired. In general, the weight ratio of warp toweft elongated members will range from about 90:10 to about 40:60, andmore preferably about 70:30 to about 45:55 (e.g., about 50:50).

Though illustrative warp and weft ranges are disclosed in the above, itis possible that others may also provide satisfactory results. Forexample, the average number of warp elongated members per unit area maybe the same as the number of weft elongated members in the same area. Itis possible that the numbers of each may vary relative to each other.For example, the average number of warp and weft elongated members perunit area may vary by 10% or less (e.g. within a 4 cm² there may be 18warp members and 20 weft members). They may vary in larger proportionsas well, such as by at least 20%, or even by at least 50% (e.g. within a4 cm² area there may be 10 warp members and 20 weft members).

It is also possible that as between the warp and weft elongated members,the thickness, width, or both of the elongated members may besubstantially the same, such that they vary by no more than about 10%.It is possible, however, that as between the warp and weft elongatedmembers, the thickness, width, or both of the elongated members may varyby 20% or more. As will be discussed in further detail momentarily, itshould also be appreciated from the above that the intermediate form mayinclude a plurality of layers, with at least two of the layers having adifferent weave characteristic relative to the other layers.

Monolithic Elongated Members and Geophysical Textiles

As the following discussion illustrates, elongated members useful inaccordance with the present teachings may be of a substantiallyhomogenous construction, i.e., a monolithic structure where thecomposition is the same throughout. They may also have a variation inthe composition across the width, thickness or diameter, such as isachievable through a multiple-layer construction. As to the former,though windings of a monolithic elongated member structure are possible,more commonly, monolithic elongated members will be in a woven form, asa material known generally as a geophysical textile.

Indeed, among the many unique features of the present invention is theability to make effective use of the above-referenced monolithicmaterials, such as the mentioned geophysical textiles. These materialscurrently commonly find many civil engineering applications (althoughthe present teachings are not so continued), such as one or more oferosion control/soil retention, silt fence, landscaping, reinforcement,separation (e.g., for paving), drainage and other applications. Quiteoften, geophysical textiles exhibit a relatively high bidirectionalstrength and stiffness and comprise woven fibers that may not beconsolidated and may thus exhibit some amount of permeability,permittivity or both. Properties of geophysical textiles can vary over awide range. By way of example, it may be possible that the geophysicaltextiles will exhibit a grab tensile strength (per ASTM D4632) of atleast about 0.3 kN, and more specifically ranging from about 0.5 toabout 3 kN, and a grab tensile strength elongation (per ASTM D4632) ofat least 10%, e.g., about 15%, with levels of 50% or higher alsopossible. The geophysical textiles will exhibit a Mullen burst strength(per ASTM D3786) of at least about 1000 kPa, and more specifically fromabout 2000 to 10,000 kPa (e.g., about 3000 to 7000 kPa), and a puncturestrength (per ASTM D4833) of at least 0.20 kN, and more specificallyranging from about 0.25 kN to about 0.80 kN. Examples of commerciallyavailable geophysical textiles include polypropylene fabrics, such asthose offered under the name Propex® (from Propex Fabrics (Georgia)), aswell as geophysical textiles offered by Don & Low under the designationLOTREK, by Mirafi (Ten Cate Nicolon) under the designation GEOLON, andother vendors such as US Fabrics, Inc. and LINQ Industrial Fabrics, Inc.

It will be appreciated that geophysical textiles useful in accordancewith the present invention may be fabricated from one or morethermoplastic (e.g., a polyester, a polyolefin, or a combinationthereof). Of course, the various individual thermoplastic materialsdisclosed herein can be formed into a geophycial textile. Geophysicaltextiles commonly (but need not necessarily) include an orientedportion, and typically articles made herein using a woven geophysicaltextile will include elongated members that have been processed (e.g.,stretched) to include an oriented portion, especially a portion thatexhibits substantially preservation of its initial morphology. Thoughone preferred approach contemplates the use of woven geophysicaltextiles, it is also possible that the geophysical textiles will benonwoven (e.g., prepared from staple fibers, continuous filaments orboth that are typically needle-punched and heat-bonded). Geophysicaltextiles typically will be prepared from slit films or extrudedmonolfilaments or the like, and thus, commonly will been processed toinclude an oriented portion. But it is possible that the textile mayincorporate one or more multi-filaments. In yet another aspect of theinvention, the geophysical textile may include one or more naturallyoccurring fiber, such as jute, hemp, or the like.

As will be appreciated from the discussions herein, a geophysicaltextile material may be employed in various of the embodiments disclosedherein. By way of example, without limitation, a geophysical textile maybe overmolded in accordance with the teachings herein; combined in amultiple layer intermediate form with one or more other geophysicaltextiles, multiple layer woven or wound intermediate form or both; mayemploy one or a combination of the homo-polymers or copolymers herein;or any combination thereof.

Multiple Layer Elongated Members

Turning now to a more detailed discussion of other aspects of elongatedmembers, one common approach to the technology disclosed herein is theemployment of a multi-layer elongated member as a pipe reinforcementmaterial. In particular, a multi-layer elongated member commonly willemploy at least a first surface portion and a second portion thatadjoins the first portion, wherein the first portion and the secondportion differ in composition, polydispersity, morphology, melt rate, orany combination thereof. For example, one specific approach envisions atleast one elongated member of a first thermoplastic material and havinga surface portion capable of melting prior to an adjoining portion, suchas oriented adjoining portion.

The present teachings advantageously afford the ability to makeelongated members such as a tape using a single polymer (e.g., a polymerA or B, by itself, such as described previously in the context ofgeophysical textiles) or a plurality of adjoining polymers (e.g.,polymer A and polymer B-referred to herein as an A-B componentstructure, such as A-B, A-B-A, A-B-C, A-B-C-D, etc. or any combinationthereof, such as A-B-D, A-B-C-B-D, A-C-B, or otherwise, where the C andD designations denote without limitation yet additional potentialpolymers, for example, as may be encountered with the microlayerteachings presented herein). When different polymers are employed withinan elongated member they may each be of the same composition or adifferent composition. They may be from the same general family ofpolymers (e.g., polyolefins), or different. They may be from the samespecific type of polymer within a family (e.g., polypropylene), but varyrelative to each other with respect to some characteristic such asweight average molecular weight, polydispersity, morphology, melt rateor other melt characteristic, or any combination thereof. It should beappreciated that one or more of the components (e.g., A, B, C, D or someother component) need not necessarily be a polymer, but may be anadditive, or other functional material.

Turning first to multiple layer embodiments, such as may be encounteredin a material that includes components A and B (e.g., an A-B-A elongatedmember) typically, the A and B components will be arranged in layeredrelation relative to each other (e.g., FIG. 1A, side-by-side (such as abi-component material)) or in a core/sheath relation (e.g., FIG. 1B).The B component may be covered only partially, such as by exposing atleast one side (see, e.g., FIG. 1A showing two exposed sides), orcompletely about its periphery by the A component (as in FIG. 1B). Thelayered embodiment of FIG. 1A, it will be appreciated, can also includerounded edges or surfaces. Ordinarily the component B will be locatedwithin an interior portion of the elongated member, and will be a highermelting point material than the component A. Thus, the structure andmaterial of the elongated member will permit the component A to meltbefore the component B, and will enable the substantial retention ofmorphology in at least the component B. As will be appreciated, therelative amounts of component A to component B may vary. In someapplications, for example, it is possible that a relatively small outerlayer (e.g., an A layer of an A-B-A multiple layer combination) isapplied to a relatively large interior layer (the B layer). Otherapplications may employ a larger outer layer. For example, for an A-B-Acombination the relative volumes of each may range from about 1:1:1 to1:35:1, more specifically about 1:10:1 to 1:25:1, and still morespecifically about 1:15:1 to 1:20:1 (e.g., 1:17:1). An A-B core-sheathstructure may use similar proportions, but omitting one of thecorresponding amounts for one of the outer layers. For example, insteadof 1:1:1, the proportion would become 1:1.

As introduced in the above, an elongated member (e.g. a coextruded tape)made with these components (e.g., an A-B-A multiple layer elongatedmember) preferably comprises about 1 to 20 wt % of component A and about80 to 99 wt % of component B. Though such relative proportions will betypical of a large number of various elongated members in accordancewith the present teachings, it should not be considered limiting. Forexample, for some applications, the employment of larger proportions ofcomponent A relative to the component B in an elongated member is alsopossible and good results are obtainable in accordance with theteachings herein. For example, it is contemplated that the amount of thecomponent B (e.g., a polymer including polypropylene, such as ahomopolymer of polypropylene) may be lower than about 50% by weight ofthe overall weight (e.g., less than about 45% by weight of the overallweight, or possibly about 10 to about 45% by weight of the overallweight, or even more specifically about 20 to about 40% by weight of theoverall weight).

In general, where an elongated member includes at least a component Aand component B, typically, the melting points (which may occur over arange of temperatures) of the components A and B will differ, with themelting point (namely, the peak melting temperature for materials thathave a melting range) of the component A being below the melting pointof component B. In addition, the higher melting point material typicallywill be at least partially oriented (e.g., mono-axially or bi-axially).The relative melting points may differ by as small as about 5° C., butwill more typically vary by at least about 10° C., more preferably atleast about 20° C., and in one specific example may vary by as much asat least about 25° C. (e.g., about 30° C.) or higher. For example,without limitation, component A may have a melting point of about 130°C. and component B may have a melting point of above about 160° C. As aresult of the spread of the temperatures for the melting point, whatresults is that a processing window is realized within which thecomponent A is able to flow and fuse with adjoining material, forachieving consolidation upon cooling. In the meantime, by maintainingthe processing temperature of the component B at below its meltingpoint, the risk can be reduced that the component B will suffersignificant degradation to its initial morphology, and compromise to itsproperties, such as the overall high flexural modulus of the elongatedmember. In turn, additional benefits can be realized by the ability uponconclusion of processing, and especially in finished articles, torealize a substantial preservation of the initial morphology within theelongated member. In addition to the ability to retain morphology,consolidating near the lower end of the temperature range has theadditional benefit that the elongated component will be generally lessprone to relax or shrink.

As discussed above, it is seen that the reference melt characteristictemperatures selected for discussion are the melting points (such asobtainable by differential scanning calorimetry according to ISO11357-3). It should be realized that for some materials, the meltingpoint may not be sharply defined (for example, because it occurs over arange of temperatures). Accordingly, for such materials, the skilledartisan with appreciate that reference to a melting point generallyrefers to the peak melting temperature. Moreover, in some instances, itmay be more convenient to employ an alternative similar approach by thesubstitution of another related measure of the melt characteristic ofthe material, glass transition temperature or the polymeric softeningtemperature, the peak temperature of crystallization (e.g., as describedin WO2004/033509 (incorporated by reference)), or even the sealinitiation temperature (e.g., as described in Isothermal CrystallizationKinetics and Morphology of Polypropylenes and Propylene/Ethylene (P/E)Copolymers; by C. H. Stephens, B. C. Poon, A. R. Kamdar, S. Chum, P.Ansems, K. Swogger, A. Hiltner and E. Baer. (Presented at the SPE ANTECConference in Chicago, Ill., in May 2004), incorporated by reference),for the respective components.

Effectively, therefore, the desired spread in relevant meltcharacteristic temperature of the respective components A and B (e.g., adifference of about 5, 10, 20, 25, or 30° C. or more in such meltcharacteristic temperature of the polymer) is selected generally so thatfusion of the component A can occur without reduction to the enhancedmechanical properties that component B possesses relative to component Ain their initial solid states.

One potential benefit of a multiple layer structure is the ability toprepare the elongated member to provide differences in characteristicswithin respective portions of the elongated member, so that theelongated member can be precisely tailored for a particular application,for a particular set of processing conditions, or a combination thereof.As will be seen from a review of the discussion herein, the manner ofachieving an advantageous multiple layer structure may vary dependingupon the attendant results sought, and a variety of techniques may beemployed for realizing a multiple layer structure. For example, one ormore of the portions may be coated, laminated, adhered, surface treated(e.g., atmospherically treated (e.g., oxidized or the like), a coronadischarge, or other plasma treatment), flame sprayed, ionized,irradiated, powder coated, hot melt applied, or otherwise joined ontoanother portion. In another approach, the different portions may besubjected to different heat treatments, different strain treatments orother processing conditions. In still another, different portions arecoextruded together. Combinations of the above approaches may also beemployed.

In more detail, typically the elongated members of the present inventionwill be derived from a film (which film may be un-oriented, but moretypically will be monoaxially oriented, biaxially oriented orotherwise). For example, it is quite typical that the elongated members(and particularly elongated members selected from at least one of theyarns, tapes, fibres or filaments) could be made by subjecting a moltenpolymer (e.g., at a melt temperature of the polymer, such as about 200to 240° C. for various polyolefins or other thermoplastics) to a blownfilm process (e.g., an air quenched blown film process, such asdiscussed in WO2005035598, incorporated by reference), by a cast film orsheet (e.g., quenching an extruded molten polymer using a chilledroller), or by film or sheet extrusion (e.g., such as through awater-bath). Combinations of these approaches may also be employed. Thefilm or sheet can then be slit into predetermined widths, using asuitable cuffing operation such as sonic slitting, hot knife slitting, acombination thereof or otherwise. Slit films can then be processed intothe desired denier (e.g., from about 1000 to about 20,000, e.g.,possibly greater than about 13,500) and weight (e.g., a weight of atleast about 7 g/denier and possibly at least as high as about 9 g/denieror higher, and even more specifically higher than about 10 g/denier)through a heating phase (such as by use of a hot table) or a stretchingoperation (optionally employing a stretching oven for elevatedtemperature stretching). For some embodiments, slit films may have a texcharacteristic (the weight of length of about 10 km tape) of from about60 to 300. Slit films can also be fibrillated and wound onto bobbins forlater use in final products. The entire process as described typicallywill be a continuous process, but need not be.

By way of further particular example, one other possible approach forforming an elongated member (and particularly an elongated memberselected from yarn, tape, fibre or filament) may be to subject a moltenpolymer (e.g., at a melt temperature of 90 to 230° C.) to a step ofextrusion (e.g. following which it passed through a water bath at atemperature of 20 to 40° C.) with a suitable die (optionally with atapered opening) such as a sheet die (e.g. a Collin Teachline extruder)to form a cast sheet of up to about 10 mm thickness (more typically itis about 1 mm thick). The sheet is slit into widths of about 1 to 20 mm,more particularly about 2 to 10 mm (e.g., about 5 mm) and stretchedbetween goddets in one or more heated ovens to a draw ratio of about 2to 10 (e.g., about 5) or higher at about 50 to 70° C. (e.g., 60° C.).The resulting yarn, tape, fibre or filament may then be furtherstretched at one or more elevated temperatures (e.g., greater than about120° C., such as at a temperature of about 140 to 200° C. (e.g., about170° C.)) at one or more additional draw ratios of at least about 2 to 8(e.g., about 3.5), which results in a desired thickness (e.g., about 0.3to 2 mm, more specifically about 0.05 to 0.3 mm (particularly when thecast sheet is about 1 mm thick) or possibly larger or smaller). It mayalso be possible to include one or more stretching steps at atemperature below the melting point of the stretched polymer. Onepossible stretching operation involves stretching a material thatincludes a polypropylene homopolymer at a temperature of about 17° C. toa draw ratio of at least 5, more specifically at least 10, and stillmore specifically at least 15.

In another approach, such as one for monoaxially-oriented processing, aflat or round profile is extruded and then oriented according totechniques for forming a monoaxially-oriented elongated member to obtainthe desired tenacity and denier. Then, the elongated member may be woundonto a bobbin. It will be appreciated that the above processes aresuitable for adaptation for forming an elongated member that includestwo polymers, such as by coextrusion of the two polymers to form a tapeor filament.

In the course of manufacture of a multiple-layer elongated member, italso is desirable to substantially approximate the rheology of therespective layers to help avoid build-up of undesirable shear stressesor other consequences as the material is passed through any feedblockand die assembly.

As can be gleaned from the above, as the present teachings relate tostretching, the skilled artisan will appreciate that many alternativeapproaches to stretching are possible. It is common in many suchinstances that a film or sheet is subjected to one or more stretching(e.g., uniaxial, biaxial or otherwise) steps, such as for forming ayarn, tape, fibre or filament. Stretching can be performed in asingle-stage operation or a plural stage operation (e.g., a dual-stageprocess). Stretching typically will be done at an elevated temperature(e.g., particularly for polyolefins, greater than about 6° C., and evenmore typically greater than about 100° C., such as between about 100 toabout 200° C., more specifically up to about 190° C. (e.g., about 120 to180° C., and even more specifically for polypropylenes about 140 toabout 190° C., such as about 150° C. to 170°), it being recognized thattemperature conditions for other materials such as polyesters may beother than as set forth). Considered another way, for a system thatincludes higher and lower melting point components (such as an A-B-Atype structure), the stretching typically will occur at a temperaturethat is above the melting temperature of the lower melting pointcomponent, and within about 1° C. of the peak melting temperature of thehigher melting point component. The amount of film stretch per stage (ascompared with its isotropic melt state) can be selected as desired,ranging for example from about 2× to about 20× or higher (e.g., about 4×to 10×, about 8× to 15× or possibly about 15× to 18×, or even about 25×to 40×). Further, the stretching can be accomplished by a single stage(so that one stretch accomplishes the entirety of the stretching), orplural stage operation (e.g., a plurality of consecutive stretches).Higher or lower stretch amounts may be possible. Further, thoughdisclosed particularly for single stage stretches, a plurality ofsequential steps may also be employed for accomplishing the desiredstretch amount. During each stage the temperature of the film can bekept constant or varied over a range of temperatures. Stretching amountsherein are disclosed with reference to a comparison of the resultingelongated member with the film formed from an isotropic melt. Additionalaspects of elongated member formation will be addressed morespecifically in the discussion herein.

Desirably, however, upon completion of stretching, the elongated member(especially elongated members that are selected from a yarn, tape, fibreor filament) will exhibit an initial morphology, including anorientation (typically a monoaxial orientation, but potentially alsohaving biaxial or other orientation components). Attendant therewithtypically will be an increase in the strength and rigidity of thematerial as compared with its unstretched or relaxed state. For example,upon stretching, elongated members (especially those that include higherand lower melting point components (such as an A-B-A type structure), inaccordance with the present invention frequently will exhibit a modulusof elasticity of at least about 13 GPa, and more specifically at leastabout 18 GPa, as measured by ASTM D-638 and a tensile strength of atleast about 150 MPa, and more typically at least about 300 MPa, asmeasured by the following ASTM test method D-638. As will beappreciated, the substantial preservation of morphology (and theattendant attractive properties) is among the benefits obtainable fromthe present teachings. Of course, as will also be gleaned from thediscussions herein, the above properties are not mandatory. It is alsocommon for many of the materials taught herein (e.g., the geophysicaltextiles and others) to have a modulus of about 5 to 12 GPa.

Materials for Elongated Members

In the discussion that follows, it will be seen that particular advancesin the present technology can be achieved through one or a combinationof the selection of the particular polymer constituents for therespective layers, the size of the respective layers, the manner ofmaking individual layers, or the manner of assembling the respectivelayers. In one particular aspect, it will be shown herein a recognitionthat recent technological advances in the field of polymers havesignificant applications in the field of polymer composites. Forexample, from the discussions herein, it will be seen that the presentinvention makes advantageous and unexpected use of thermal andmechanical properties of various conventional polymers as well asrecently discovered polymers.

Examples of specific polymers that can be employed in accordance withthe present teachings (whether for monolithic elongated members ormultiple-layer elongated members) the present invention include one ormore polyolefins such as thermoplastic olefins, poly(α)olefins,ethylene-based polymers, propylene-based polymers, or any combinationthereof (whether in the form of one or more of a copolymer, a blend oran alloy). In general, for multiple-layer structures, a combination ofmaterials will be employed wherein a lower melting point polymer iscoextruded with a higher melting point polymer to form the layers.Though either layer may be amorphous or at least partially crystalline,specific examples taught herein have the higher melting point polymerlayers being of a relatively high degree of crystallinity (e.g., atleast 30%, and more typically at least 50%, or even 70%). As discussedthroughout, one of the advantages that are possible following theteachings herein is that, even subsequent to processing of the materialsfor fabricating a composite article, the material of at least the highermelting point layer exhibits a substantial preservation of itsmorphology, such as by retaining a relatively high degree ofcrystallinity (e.g., at least 30%, and more typically at least 50%, oreven 70%) even after a step of consolidation.

Ethylene-based polymers include but are not limited to ethylenehomopolymer or interpolymers of ethylene with at least one C₃-C₂₀α-olefins, and may be referred to as ultra high density polyethylene(UHDPE), ultra high molecular weight polyethylene (UHMWPE), high densitypolyethylene (HDPE), medium density polyethylene (MDPE), low densitypolyethylene (LDPE), linear low density polyethylene (LLDPE), very lowdensity polyethylene (VLDPE), ultra-low density polyethylene (ULDPE), orsubstantially linear ethylene polymer (SLEP). Ethylene-based polymersmay be made via one or more various processes, including but not limitedto high pressure, solution, slurry, or gas phase reactions, using one ormore various catalyst systems such as chromium (Cr), Ziegler-Natta(Z-N), metallocene, constrained geometry (CG), or other advanced,non-metallocene, complexes. For use as a lower melting point component Ain an A-B structure, it is desirable to employ a copolymer of apolypropylene having one of the above ethylene-based polymers, orpossibly another α-olefin (e.g., butene, or the like). Other possiblematerials include blends of polypropylene copolymers with(co)polyethylene (e.g., heterophasic polypropylenes).

Propylene-based polymers include but are not limited to propylenehomopolymer or interpolymers of propylene with at least one of C₂ orC₄-C₂₀ α-olefins, and may be referred to as homopolymer polypropylene(hPP), random copolymer polypropylene (RCP), high crystallinepolypropylene (HCPP), rubber-modified polypropylene (generally a hPP orRCP matrix with a disperse “rubber” phase), also referred to as impactor block copolymers (ICP), or propylene-ethylene copolymers.Propylene-based polymers may be made via various processes, includingbut not limited to solution, slurry, or gas phase, using variouscatalyst systems such as Ziegler-Natta (Z-N), metallocene, or otheradvanced, non-metallocene complexes. Propylene-based polymers may beisotactic, syndiotactic or atactic, but preferably are isotactic.

Examples, of particularly preferred polyolefins for the lower meltingcomponent (e.g., component A in an A-B-A elongated member) includepropylene-ethylene copolymers (which may be rubber-modified); morepreferably with narrow molecular weight distribution such as thoseavailable from Dow Chemical under the designation VERSIFY, or ExxonMobilunder the designation VISTAMAXX, or a combination thereof. Even morespecific examples of polymers that may be employed in accordance withthe present teachings (especially for use as a lower melting pointcomponent, e.g., component A of an A-B-A combination, or as one or morelayers of microlayer materials described herein) include those disclosedin WO 03/040201 A1, published US Application No. 2003-0204017, and U.S.Pat. No. 6,525,157, all of which are incorporated by reference. Forexample, the material may be a propylene-ethylene copolymer in thesubstantial absence of dienes. Another potential candidate for thecomponent A of an A-B-A combination, or as one or more layers ofmicrolayer materials described herein, is a polypropylene homopolymermade with a metallocene catalyst such that it exhibits a relatively lowmelting point. Commercial examples of such materials include ACHIEVE(available from ExxonMobil), and METOCENE (available from Basell); seealso Kunzer and Wieners, Kunstoffe Plast Europe 86 (May 1996) 5, pp.666-670, incorporated by reference. An example of one commerciallyavailable polyethylene material that may be used herein is thatavailable under the trade designation AFFINITY, from The Dow ChemicalCompany.

In one approach, the copolymers may be made in a metallocene catalystprocess that employs a single reactor, in steady state. In anotherapproach the copolymer may be made using a nonmetallocene metal-ligandcomplex (e.g., metal-centered, heteroaryl ligand catalyst in thepresence of an activating co-catalyst such as alumoxane). Of courseother catalyst approaches may be employed, such as discussed previously.In one embodiment, the copolymer includes from about 5% to 25% by weightethylene-derived units, and from about 75% to 95% by weightpropylene-derived units, the percentages by weight based on the totalweight of propylene- and ethylene-derived units. As little as about 3%by weight (or less) of ethylene-derived units is also possible.

A preferred propylene-ethylene copolymer for use herein (whether aloneor in combination with another polymer, such as a polypropylenehomopolymer or random polypropylene, and whether used in an outer layer(e.g., a lower melting point layer) or an inner layer (e.g., a highermelting point layer)) preferably is a specialty propylene-ethylenecopolymer and thus has a combination of two, three or more (e.g., acombination of all) of the following characteristics: a) a MolecularWeight Distribution (MWD) of about 1.5 to about 4 (e.g., 2 to 3), b) aMelt Flow Rate (at 230° C.)(MFR) (per ASTM D1238) of at least about 0.3(e.g., about 0.5 g/10 min), and more specifically about 0.3 to about 50g/10 min (e.g., 2 to 25 g/10 min), c) a density (per ASTM D792) of about0.80 to about 0.95 g/cc, and more particularly about 0.85 to 0.91 (e.g.0.858 to 0.888 g/cc); d) a comonomer content of about 3 to 25 wt %(e.g., 5 to 15 wt %); e) a Glass Transition Temperature (Tg) of about 0to about −50° C. (e.g., −15 to −35° C.); f) a Melting Range from about40 to about 160° C. (e.g., 50 to 135° C.); g) a Shore A Hardness fromabout 25 to about 100, and more particularly about 40 to about 90 (e.g.,50 to 75); and h) a flexural modulus (per ISO 178) of about 5 to 1000MPa, or more particularly from 8 to 325 MPa (e.g., 10 to 280 MPa), orhigher (e.g., in excess of 2000 MPa). By way of example, withoutlimitation, such material may have a flexural modulus of about 8 toabout 325 MPa (e.g., about 10 to 280 MPa), an ethylene content of about3 to 25 wt %, and optionally a peak melting peak below about 135° C., aShore A Hardness from about 25 to about 100, and more particularly about40 to about 90 (e.g., 50 to 75); or a combination of both. Acommercially available example of one such copolymer is available fromthe Dow Chemical Company under the name VERSIFY. In one particularexample, the above characteristics are observed in the elongated memberand thereafter in a resulting composite article prepared according tothe teachings herein.

The material preferably commonly may be one or more of a randomcopolymer, a hetero-phasic copolymer with a random matrix, a clarifiedcopoloymer (e.g., clarified using a nucleator/clarifier taught herein)or an isotactic copolymer.

In general, particularly for elongated members that have an A-Bcomponent structure (e.g., an A-B-A material) not only will component Binclude a polymer that has a higher melting point than that in componentA, typically the component B material will be an oriented material thatexhibits substantially retained morphology after processing greaterstiffness, toughness, and possibly even tensile strength than thematerial of component A. Thus, it is common that the component B will bea major contributor to the overall mechanical properties of theelongated member.

In one particular illustrative embodiment, the component B will includeas a major portion, a relatively high stiffness material, andparticularly a polyolefinic polymer. In one aspect, it is particularlydesired that the component B will include or even consist essentially ofan oriented polypropylene. Typically the molecular weight distributionof the component B may be narrow, medium or broad. For variousapplications, the component B that is employed may be characterized alsoas a multi-modal nucleated material. One particularly preferred class ofpolymers for the higher melting point material (e.g., the component B)will have a flexural modulus per ASTM D 790, ISO 178 of greater thanabout 1000 MPa (e.g., greater than about 1200 MPa such as about 1500MPa) or higher. Specific examples include a homopolymer polypropylene(hPP), a random copolymer polypropylene (RCPP) or a combination thereof.Examples of commercially available materials include those availablefrom The Dow Chemical Company (e.g., offered under the designationINSPIRE), ExxonMobil (e.g., offered under the designations PP9122,PP9852E1, PP2252, PP4712E1, PP4772, PP4792E1 or the like), Basell (e.g.,offered under the designation ADSTIF, METOCENE, or MOPLEN), or Borealis(BORMOD). Another material that may find suitability in the A or Bcomponents of the present teachings is ADFLEX (e.g., Z104), availablefrom Basell.

One particular example of an attractive polypropylene for use in thepresent includes or more specifically consists essentially of anisotactic polypropylene homopolymer (e.g., as prepared and analyzed inaccordance with the teachings of WO 20041033509 and US 20040122196,hereby incorporated by reference; see Appendix herein for additionalteachings of materials characterizations analyses). Accordingly, for usein the component B, one example of a specific polypropylene ischaracterized by a combination of two, three, four, five, six or more(e.g., a combination of all) of the following characteristics: a) amolecular weight distribution (M_(w)/M_(n)) of less than about 5.5, asmeasured by gel-permeation chromatography according to the teachingspublished in WO 2004/033509 and US Patent Application No. 20040122196(see Appendix), b) a melt flow rate (at 230° C.)(per ASTM D1238) of lessthan about 25 g/10 min, more preferably less than about 10 g/10 min, andmore preferably less than about 7 g/10 min (e.g., less than about 5 g/10min), c) a 1% secant flexural modulus (per ASTM D790-00) of greater thanabout 2000 MPa (e.g., greater than about 300,000 psi), d) less thanabout 2% (e.g., less than about 1%) xylene solubles, as measuredaccording to the teachings published in WO 2004/033509 and US PatentApplication No. 20040122196 (see also, Appendix herein), e) a haze (perASTM D1003) of less than about 25%, f) a crystallinity of at least about30%, more specifically at least about 50%, and still more particularlygreater than about 70%, as measured by differential scanning calorimetryaccording to the teachings published in WO 2004/033509 and US PatentApplication No. 20040122196 (see also, Appendix herein), g) an isotacticpentad/triad ratio of greater than about 70%, more preferably greaterthan about 85% and still more preferably greater than about 95%, andeven still more preferably greater than about 99%, using nuclearmagnetic resonance (NMR) according to the teachings published in WO2004/033509 and US Patent Application No. 20040122196 (see also,Appendix herein); and h) a crystallization temperature (e.g., asmeasured according to the teachings of WO2004/033509 and US PatentApplication No. 20040122196 (see also, Appendix herein)) of greater than133° C. In one illustrative example, it is possible that the pentadisotacticity is at least 96%, more preferably at least 97%, and mostpreferably at least 98%. Typically, the polypropylene homopolymer willexhibit a peak melting point of at least 160° C. (e.g., at least 165° C.or even 170° C.). By way of example, the polypropylene homopolymer willexhibit a peak melting point of at least 160° C. (e.g., at least 165° C.or even 170° C.), and a crystallinity of at least about 30%, morespecifically at least about 50%, and still more particularly greaterthan about 70%, an isotactic pentad/triad ratio of greater than about70%, more preferably greater than about 85% and still more preferablygreater than about 95%, and even still more preferably greater thanabout 99%, or both such isotacticity and crystallinity. In a particularexample, the polypropylene homopolymer further will exhibit a 1% secantflexural modulus (per ASTM D790-00) of greater than about 2000 MPa Inone particular example, the above characteristics are observed in theelongated member and thereafter in a resulting composite articleprepared according to the teachings herein. For example, it is possiblethat the material of the component B actually exhibits an increase inpeak melting point in a resulting consolidated composite article (e.g.,by as much as 3, 5 or even 8° C.) as compared with its peak meltingpoint prior to consolidation.

For example, one specific polypropylene is characterized by anM_(w)/M_(n) of less than about 7, a melt flow rate of less than about 7g/10 min, a 1% secant flexural modulus of greater than about 2000 MPaand less than 2% by weight xylene solubles. An example of suchpolypropylene is discussed in US2004/0122196 entitled “Highlycrystalline polypropylene with low xylene solubles” and WO2004/033509entitled “Highly crystalline polypropylene with low xylene solubles”,both incorporated by reference. where techniques for determination ofthe above characteristics are also taught.

It is also recognized herein that additional advantageous results may beobtained (e.g., to aid in stretching) by including within the highermelting point layer such as component B (e.g., as a blend, a copolymer,or a combination thereof, an optional minor amount (relative to thecomponent B) of a lower melting point polyolefinic copolymer, such as apropylene-ethylene copolymer (e.g., of the type described above, such asVERSIFY™ copolymer available from The Dow Chemical Company). Suchco-polymer preferably has a combination of two, three or more (e.g., acombination of all) of the above-discussed characteristics for aspecialty propylene-ethylene copolymer. Without intending to be bound bytheory, it is believed that the inclusion within the component B of alower melting point polyolefinic material functions to help bond thecomponent B layer to the component A layer; it also is believed that thepresence of the lower melting point polyolefinic material helps to bondindividual fibrils within the component B layer to each other. Likewiseit may be possible to vary the characteristics of component A, byincluding in the component A minor amounts of a material disclosedherein for the component B.

More specifically, as used in the component B of the elongated member,one preferred approach is to employ a polypropylene homopolymer (e.g.,one prepared in accordance with the teachings of WO 2004/033509 and US2004122196, hereby incorporated by reference) in an amount of at leastabout 70 parts (e.g., 80 to 100 parts) by weight of the component B. Ifthe optional minor amount of the polyolefinic copolymer (e.g., the abovediscussed propylene-ethylene copolymer) is used, it will be present inan amount of up to about 30 parts (e.g., from about 0 to 10 parts) byweight of the component B.

As mentioned, the higher melting point polymer (e.g., the component B inthe illustrative embodiment including an A-B structure) is typically amajor contributor to the overall mechanical properties of the elongatedmember. Though not required in every instance, it is frequently desiredthat the component B exhibit good stretching characteristics,particularly under elevated temperature (e.g., about 170° C.).Accordingly, it may be possible that the component B exhibit a drawratio (i.e., the ratio of the initial to final thickness of the body) ofat least about 8, more preferably at least about 12, and still morepreferably at least about 16 or higher, without rupture or significantcompromise to its overall performance. It is also recognized herein thatby incorporating an amount of propylene-ethylene copolymer (such as thespecialty copolymer as described above) in the component B, suchrelatively high stretch is possible. From this, it will also beappreciated that, even though the presence of the copolymer initiallywill reduce the stiffness of the component B, substantial gains in thestiffness of the final stretched material will be realized, because theenhanced stretch capabilities of the material will afford greateropportunity for stiffening to occur during the stretch.

As for examples of particular preferred materials for the higher meltingpoint material (e.g., the material B in the illustrative A-B structurecombination), use of a high stiffness (and in one preferred approach, ahighly isotactic) propylene homopolymer. Examples of such homopolymersare described above and in US2004/0122196 entitled “Highly crystallinepolypropylene with low xylene solubles” and WO2004/033509 entitled“Highly crystalline polypropylene with low xylene solubles”, bothincorporated by reference, will permit even higher stretch capabilities(e.g., at least about 10×, more preferably at least about 15×, and stillmore preferably at least about 20×) in a single step stretching process,thus reducing or even eliminating the need for additional stretchingsteps, annealing steps that may be employed herein or both. Of course,it will be appreciated that the employment of a highly crystallinepolypropylene is desired, it is not mandatory, and good results are alsoobtainable using polypropylenes that are not highly crystalline (e.g.,various conventional polypropylenes derived by Ziegler-Natta catalyst,mini-random polypropylene copolymer, as well as others discussedherein).

The material selected for individual layers of the elongated membersherein need not necessarily contain only a copolymer (e.g., apropylene-ethylene copolymer) or a homopolymer (e.g., a polypropylenehomopolymer). Rather, it is possible, that copolymers, blends, alloys orother combinations of copolymer and homopolymer may be employed. In thismanner, it may be possible to further tailor the characteristics withineach individual layer. For example, for a situation in which twocomponents (e.g. component A and component B) are utilized, component Amay comprise polypropylene homoploymer and a propylene-ethylenecopolymer. For example the polypropylene copolymer may comprise about 0to 100 parts by weight of component A, while the propylene-ethylenecopolymer may comprise from about 5 to 100 parts by weight of thecomponent A. Likewise, an amount of another relatively elastic material(e.g., a polypropylene plastomer or elastomer, a propylene-ethylenecopolymer or a combination) might be added to the component B forhelping to increase its draw ratio (e.g., in an amount up to about 10wt. %).

The use of a mini-random (i.e., <2 wt. % C₂) propylene-ethylenecopolymer in either or both of the A or B components is alsocontemplated as within the scope of the present teachings. It is alsocontemplated that the material in either or both of the A or Bcomponents will be free of a styrene polymer.

Additives for Use in or with Elongated Member Materials

In one embodiment, the material used for the elongated members, whetheras a monolithic material or as a component of multiple-layer elongatedmember (e.g., component A, B or otherwise) may also include anon-migratory process aid or surface modifier agent selected to modify(increase or reduce) the surface friction characteristics, the scratchand abrasion resistance characteristics, or both of the material.Preferably, such surface property agent is present in a relatively smallamount, e.g., in an amount less than about 10% by weight of the material(e.g., up to about 4%). Quite typically, the surface property agentselected will be such that it reduces surface friction of the material,increases scratch and abrasion resistance of the component, improveshandling of the elongated member during formation of the intermediateform (e.g., improved weaving characteristics) or more preferably acombination of each. Though use of such surface property agent is morelikely for an exposed outer layer (e.g., a component A of an A-Bstructure), it may also be employed elsewhere in the elongated member,such as in a higher melting point material of component B.

Particular examples of classes of materials suitable for use as thenon-migratory process aid or surface modifier agent include silicones,polyolefins, halogenated polymers (e.g., fluorinated thermopolymers), orany combination thereof. One particularly preferred agent comprises ahigh molecular weight silicone, and particularly an ultra-high molecularweight siloxane (e.g., a functionalized or non-functionalized alkylsiloxane, such as a poly(diethyl siloxane) a poly(dimethylsiloxane), ora combination thereof, such as are available commercially asmasterbatches from Dow Corning, under the trade designation Dow CorningMB 50-313, MB 50-001, MB50-321 or MB50-021). Other alternatives may begleaned by reference to WO 01/12715, WO 02/08332, WO 98/13419, allincorporated by reference.

The polyolefins herein optionally may contain a relatively small amount500 ppm to 2500 ppm (e.g., 750 ppm to 1500 ppm) of a nucleator/clarifieradditive. Though the nucleator/clarifier additive advantageously may beemployed in the propylene-ethylene copolymers taught herein (and usedfor example in the component A of an A-B-A multiple layer elongatedmember), it is particularly desired for use with polypropylenehomopolymers, especially those used as component B of an A-B-A multiplelayer elongated member. It is further particularly desired for use indrawing processes that involve a single stage draw (it being optionalfor most applications in which multiple stage draws are employed). Ingeneral, the nucleator/clarifier additive is used to increase thestiffness of the films made from the resin and also to increase thecrystallization rate of certain of the polymers (e.g., the highcrystalline propylene-based polymer) during the manufacture of the airquenched blown film. This nucleator/clarifier additive will also improvethe stiffness/clarity balance of the resulting film. Any additive, whichsimultaneously clarifies and nucleates can be used. Nucleator/clarifieradditives such 2 as ADK NA-11 (Methylene-bis(4,6-di-ter-butylphenyl)phosphate sodium salt) and ADK NA-21 (Aluminum hydroxybis[2,4,8,10-tetrakis(1,1-dimethylethyl)-6-hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphoshocin6-oxidato]) are commercially available from Asahi Denka Kokai andpreferably are added to the high crystalline propylene-based polymer ofthe invention. Millad 3988 (3,4-Dimethylbenzylidine Sorbitol) availablefrom Milliken & Company is another example of a nucleator/clarifieradditive that can be utilized in the invention. Sodium benzoate or evensorbitol-based nucleation systems may also be employed in accordancewith the present teachings.

Whether employed in a monolithic material, or a multiple layer materialfor an elongated member, the material may also include one or acombination of two or more other ingredients such as other polymers(e.g., a polypropylene, a polyethylene, a fluoroelastomer, anycombination thereof, or the like), a filler (e.g., glass, talc, calciumcarbonate, or the like), an anti-fibrillation agent (e.g., PE) anucleation agent, a mold release agent, a flame retardant, anelectrically conductive agent, an anti-static agent, a pigment, carbonblack, an antioxidant, an impact modifier, a stabilizer (e.g., a UVabsorber), or any combination. For example, when these additives areemployed they typically will be employed in an amount up to about 15% byweight of the overall component (e.g., about 0 to 10 wt % of thecomponent A, component B or both, and more specifically about 2 to 8 wt%, with individual additives typically used in an amount less than about1 wt. % of the material, e.g., less than 0.6 wt. %, less than 0.5 wt. %,and even as low as about 0.2 wt. % or lower). The component (e.g.,Component A or B) may also include recycled scrap material (e.g., fromthe manufacture of component A, component B or even from the manufactureof the elongated members of the present invention). Examples of possibleadditives are taught, without limitation, in EP 0829529A1, incorporatedby reference). Examples of commercially available additives include,without limitation, ERUCAMIDE, IRGANOX B215, IRGANOX B225, MISTRON talc,IRGANOX 1010 (or a thioester), CHIMASORB 944, CHIMASORB 119, HOSTASTATFE2, IRGASTAT and TINUVIN 770. The present teachings contemplate notonly the above commercial products, but corresponding product offeringsfrom other manufacturers.

It is also possible to include in the component B (the higher meltingpoint component) of the elongated member material one or more otherpolymeric components for enhancing its properties. For example, inaddition to a polypropylene homopolymer, the high stiffness material maycomprise other thermoplastic materials such as polyethyleneterephthalate (PET), polyamide, polycarbonate, any of the otherthermoplastics described herein, or a mixture thereof. Likewise, anamount of relatively elastic material (e.g., a polypropylene plastomeror elastomer, a propylene-ethylene copolymer or a combination) might beadded to the component B for helping to increase its draw capacity.

By way of illustration, one approach to the manufacture of an elongatedmember involves the formation of a film that is coextruded so that itresults in an A-B-A combination, wherein the component A is a randomcopolymer of propylene and about 3 to 15 wt. % ethylene (e.g., about 5to 15 wt. %) (with a density of about 0.9 g/cm³), and has a meltingpoint of about 50 to about 135° C. (e.g., 100 to 140° C.), and thecomponent B is a polypropylene homopolymer with a peak melting point ofabout 150 to 170° C. (it being recognized that for some embodiments amelting point in excess of about 170° C. may be possible (e.g., fromabout 150 to 180° C. or higher). Accordingly, it is possible that thedifference in melting point between component A and B may be as littleas about 5 to 9° C., or higher than about 75° C. The relative amounts ofthe A and B components range from about 1:2:1 to 1:25:1, and still morespecifically about 1:15:1 to 1:20:1 (e.g., about 1:17:1)). The componentA or B may have any suitable weight average molecular weight, such asabout 50 to about 400 kg/mol, and more typically about 200 to about 300kg/mol.

The above is not intended to limit the present teachings. Other examplesof extruded tapes or yarns are disclosed, without limitation, in WO03/008190A1 and WO 2004028803 (both incorporated byreference)(addressing a skin layer (e.g., a component A) that includes arandom copolymer including propylene with ethylene or anotheralpha-olefin; the employment of a metallocene-based statistical polymeris also addressed). EP 0776762B1, incorporated by reference, disclosesanother example of a possible material for use as an elongated member,pursuant to which a skin layer (e.g., a component A) includes a blend ofethylene copolymer with an amount of high density polyethylene (e.g.,about 5 to 45 wt. %). U.S. Pat. Nos. 5,993,711 and 6,045,923 (assignedto Lankhorst Indutech B.V.), both incorporated by reference, alsoillustrate viable alternatives. According to the former, the profile ofthe elongated member may include one or more longitudinal ribs and/orlongitudinal grooves on one or more surfaces. According to the latter,it is possible that an elongated member may include a central layer(e.g., component B) prepared from a blend of high density polyethyleneand one or more other polyolefins, whereby the amount of high densitypolyethylene is predominant, i.e. more than about 50% by weight. More inparticular, the central layer is prepared from a blend of about 50 to 90wt. % of high density polyethylene (>940 kg/m³) and about 10 to 50 wt. %of (linear) low density polyethylene (<925 kg/m³), very low densitypolyethylene (<910 kg/m³), or combinations of these products.Additionally an amount of polypropylene may be present to improve thestrength of the material. Another possible approach in accordance withthe present invention is to form a conductive composite material,wherein the composite includes at least one conductive portion, such asfrom the presence of a conductive elongated member. The conductiveelongated member, for example, may be a coated or uncoated metal wire(e.g., a copper wire). Additional variations can be gleaned from U.S.Pat. No. 6,710,253 (assigned to Lankhorst Indutech B.V.), herebyincorporated by reference.

By way of summary, it is contemplated that in accordance with thepresent teachings a multiple layer structure may be employed thatincludes at least two layer, which differ by their melting point. Thus ahigher melting point material (which typically will be oriented) is usedin combination with a lower melting point material. The lower meltingpoint material typically will reside on an external surface of theelongated member, so that melting can occur. It is disclosed that thematerials employed may be selected from a variety of alternativematerials, with one particularly preferred combination including apropylene-ethylene copolymer as a lower melting point material layer,and a higher melting point polypropylene homopolymer layer (specificallyone that is oriented). The layers may incorporate other additives asdisclosed herein (e.g., polydimethylsiloxane or another suitablenon-migratory process aid or surface property agent). It may be possiblethat amounts (e.g., minor amounts) of the higher melting pointpolypropylene homopolymer material (e.g., is incorporated into thepropylene-ethylene copolymer as taught. Alternatively, or in additionthereto, it is also possible that the amounts (e.g., minor amounts) ofthe lower melting point propylene-ethylene copolymer material isincorporated into the polypropylene homopolymer as taught. Examples ofhighly preferred combinations of materials include a lower melting pointpropylene-ethylene copolymer of a type having characteristics similar toVERSIFY™, available from The Dow Chemical Company, in combination with ahighly isotactic polypropylene homopolymer, such as is taught above andin US2004/0122196 and WO2004/033509, both incorporated by reference.

More particularly, as seen from the above the number of combinations ofmaterials for forming a multiple layer structure including an A-Bstructure (including for microlayers as taught herein) is large. Withoutintending to be limited by the following, but for sake of summary, theteachings herein contemplate that the lower melting point layer(component A) is selected from ethylene propylene copolymer (withoutpolydimethylsiloxane), ethylene propylene copolymer (withpolydimethylsiloxane), heterophasic polypropylene (e.g., ADFLEX),ethylene propylene copolymer (without polydimethylsiloxane) withpolypropylene homopolymer, ethylene propylene copolymer (withoutpolydimethylsiloxane) with random copolymer polypropylene (e.g.,available from The Dow Chemical Company under the designation R771), orany combination thereof. For the above, an example of a preferredethylene propylene copolymer is available from The Dow Chemical Companyunder the designation VERSIFY. Further, without intending to be limitedby the following, but for sake of summary, the teachings hereincontemplate that the higher melting point layer (component B) isselected from isotactic polypropylene homoploymer, isotacticpolypropylene homoploymer with up to about 20 wt % propylene ethylenecopolymer (e.g., available from The Dow Chemical Company under thedesignation VERSIFY), random copolymer polypropylene (e.g., availablefrom The Dow Chemical Company under the designation R771) or anycombination thereof. The present teachings contemplate any combinationof the component A examples with the component B examples of the presentteachings. The materials discussed above, and especially the onesidentified in the above summary find particularly attractive in theapplications taught later herein, including their use for forming anelongated member for a winding or other intermediate form for use in thereinforcement of pipes.

Microlayers

Another approach that may be employed alone or in combination with theabove teachings of the formation of elongated members that include atleast components A and B, is the formation of elongated members thatinclude one or a plurality of microlayers. By “microlayer” it is meant alayer of relatively fine thickness, e.g., smaller than about 50 microns,more preferably smaller than about 20 microns, more preferably less thanabout 10 microns in thickness, still more preferably less than about 7microns in thickness, and even still more preferably less than about 5microns in thickness. Typically, when employed, microlayers will befabricated as an assembly of a plurality of stacked, preferablycoextruded layers that each include a polymer, co-polymer or mixturethereof. For example, each microlayer may include one or both of theabove materials described previously for the layers of components A andB in the illustrative A-B combination, or yet still another component.The number of individual microlayers in a typical elongated membertypically will vary from one to four. More commonly, however, themicrolayers will comprise at least four or more, and more specificallyat least five or more layers of materials, with each layer preferablydiffering relative to its adjoining layer.

More specifically, by way of example, one approach for the manufactureof microlayered polymeric body (e.g., an elongated member) contemplatesthat at least one first stream of a first molten or softened polymericmaterial and at least one second stream of a second molten or softenedpolymeric material are fed into a suitable apparatus (e.g., through adie of the apparatus), where they are brought together by coextruding,such as by using a microlayer melt splitter or a hemisphericalmicrolayer coextrusion feedblock, for encapsulating discrete portions ofthe first polymeric material with the second polymeric material to forma plurality of ribbon-like layers of the first polymeric material withina matrix of the second polymeric material, thereby forming a lamellarpolymeric body. In general, the materials will be selected and processedso that as they are subjected to shearing when passing through a feedtool the viscosities of the different materials will vary by less than afactor of about 3 (e.g., the viscosity of the individual polymer layersunder feed conditions will be less than a factor of about 1.5, e.g.about 1.25 or even about 1). As a result, the ribbon-like layers may besubstantially continuous in a first plane generally parallel to one ofthe major surfaces of the body and discontinuous in a second planetransverse to the first plane. In addition, it is possible that thelayers of the first polymeric material have their major interfacesaligned substantially parallel to the major surfaces of the resultingpolymeric body.

Without intending to be bound by theory, in one particular aspect, forthe microlayers herein, the present teachings provide approaches forrealizing a continuous polymer material in the direction of a draw,which has a confinement that is generally perpendicular to this drawdirection (e.g., a polymer is employed that is at least a partiallycrystalline polymer, and which is confined in a layer or domain that hasa lower degree of crystallinity). Due to such confinement, uponsolidification, the material generally exhibits a reduced amount ofentanglements which, in turn, can be used to increase the drawingcapacity of this material, thereby leading to a relatively highstiffness, strength or both in the resulting material.

One approach is to employ a structure that includes a plurality ofmicrolayers that alternate between differing materials of components Aand B. For example, this may be expressed as ((A-B)_(n)-A) where n is aninteger of 2 or greater. Elongated members where n is 3, 4 or more, 10or more, 20 or more, 50 or more, 100 or more, 200 or more and 300 ormore (e.g., 500 to 1000 layers, or possibly even 1000 to 5000 layers ormore) are also contemplated. Microlayer elongated members may befabricated using any suitable technique, such as layer-multiplyingextrusion. One approach is to coextrude a plurality of layers, such asby using a microlayer melt splitter or a hemispherical microlayercoextrusion feedblock. Optionally, extrusion may be onto a chill roll.Lamination techniques may also be used in addition to or in combinationwith a coextrusion step. In general, the polymers of the layers will beselected so that melt viscosities are approximated to help prevent layerinstability or nonuniformity, and so that the polymers used havesufficient interfacial adhesion so that adjoining layers will notdelaminate. Additional illustrative teachings are found in U.S. Pat. No.5,568,316 (also teaching the use of coextrusion devices such asdescribed in U.S. Pat. Nos. 3,773,882 and 3,884,606; 5,269,995;5,094,793 and 5,094,788, all of the foregoing patents being incorporatedby reference). See also, U.S. Pat. Nos. 5,540,978; 5,448,404; 5,339,198;5,316,703; 5,217,794; 5,126,880; 6,837,698 and EP 0647183B1, all ofwhich are incorporated by reference. See also, thesis of Dooley,“Viscoelastic Flow Effects in Multilayer Polymer Co-extrusion”,Technische Universiteit Eindhoven (2002)(ISBN 90-386-2983-4),incorporated by reference; and Rastogi, et al. “Heterogeneity in PolymerMelts from Melting of Polymer Crystals”, Nature Materials Vol. 4 (August2005)(published online on 24 Jul. 2005) incorporated by reference; Jin,et al., “Structure of Polypropylene Crystallized in ConfinedNanolayers”, PPS-20: Polymer Nanotechnology Symposium (20-24 Jun. 2000)incorporated by reference. It should be recognized, however, thataspects of the invention contemplated that the selection of thematerials for use herein does not require any specific degree ofreflectance within any layer or combination of layers. Accordingly, itis contemplated that resulting elongated members reflect less than 40%(or even less than 20%) of visible light incident on the body. Likewise,the materials may be free of any coloring agent for giving the body ametallic appearance. They may also be selected without regard toindividual optical thicknesses of the constituent layers, or the sum ofthe optical thicknesses.

Though adjoining layers of the microlayers may be of the same materialtype, more typically, as with the non-microlayer multiple layerembodiments taught herein, the materials of adjoining layers will differfrom each other in at least one characteristic, such as composition,orientation, degree of crystallization, molecular orientation, molecularweight, melt rate, peak melting temperature, glass transition peak,temperature of crystallization, seal initiation temperature, softeningpoint, molecular weight distribution or any combination thereof. Forexample, different polypropylenes may be combined, differentpolyethylenes may be combined, different polyethylene terephthalates(PETs) may be combined or the like. Furthermore a polypropylene may becombined with a polyethylene, a PET combined with a polypropylene, or apolyamide combined with a polyethylene or the like. Any of thethermoplastic materials discussed herein may be used in the microlayerelongated member, and the microlayer teachings are not confined topolyolefin polymers. For example, the polyolefinic materials describedabove for the components A and B can be selected for each of the layersof the microlayered structure.

It is also possible that one or more of the microlayers may include apolymer (or a copolymer including such a polymer) selected frompolycarbonate, polyvinylchloride, (meth)acrylonitrile, (meth)acrylate,polyurethane, thermoplastic elastomer, thermoplastic olefin, polyamide(e.g., nylon 6, nylon 6,6 or otherwise), polysulfone, polyester,polyalkylene terephthalate (e.g., poly(ethylene terephthalate),poly(butylene terephthalate), poly(1,4-cyclohexanedimethanolterephthalate) or otherwise), polyalkylene naphthalate (e.g.,poly(ethylene naphthalate)), acrylonitrile butadiene styrene,polyarylene sulfide (e.g., polypheylene sulfide), thermoplasticurethane, polyphenylene ether (PPE), polystyrene, or any combinationthereof (whether in the form of a copolymer, a blend or an alloy).

Examples of particular A-B combinations for individual microlayersinclude, without limitation, polypropylene homopolymer and polypropylenecopolymer; polypropylene and propylene-hexane co-polymer HDPE andethylene copolymer; polyamide (at least partially aromatic or not, andwhich may include a copolyamide) (e.g., Nylon 6, Nylon 6,6, Nylon 46,Nylon 11, Nylon 12, Nylon 6.6T) and polypropylene; poly(ethyleneterephthalate) and another polyester, such as poly(butyleneterephthalate), poly (trimethylene terephthalate), or both;poly(ethylene 2,6-naphthalene) or poly(cyclohexanedimethanolterephthalate) with one or more of poly(ethylene terephthalate),poly(butylene terephthalate) or poly (trimethylene terephthalate);polyolefin homopolymers and copolymers (e.g., polybutene and poly 4methylpentene (e.g., TPX Methylpentene Copolymer from Mitsui).

In addition, optionally (and having application herein for multi-layerstructures apart from only microlayers), a tie-in layer or anintermediate bonding agent (e.g., adhesive, primer or otherwise) layer,may be used between adjoining layers of multi-layer elongated membermaterials, such as between adjoining layers of a microlayer material. Inthe context of polyolefinic multi-layer materials, typically the tie-inlayer or an intermediate bonding agent layer typically includes apolyolefin with a functional reactive group. The use of a tie-in layeror an intermediate bonding agent layer is particularly useful where thecompositions of the layers are chemically disparate. For example, when apolyolefin is used as one layer and a polyester or polyamide as theother layer, a layer that includes a polyolefin with a functionalreactive group (e.g. a layer including a coupling agent such as maleicanhydride-grafted polypropylene modifiers, available under thedesignation Polybond® (from Crompton-Uniroyal Chemical, a polyolefinwith an epoxy functionality, a polyolefin with a (meth)acrylate (e.g.,glycidyl methacrylate) or (meth)acrylic acid functionality, orotherwise) may be used to increase the bonding strength between thelayers. It is also possible to employ a tie-in layer or intermediatebonding agent that includes a copolymer that includes a polyethylene, apolypropylene or a mixture thereof. For example, without limitation, onepossible approach might be to employ two or more microlayers that arepolyolefinic homopolymers (e.g., polypropylene or polyethylene), and tobind such microlayers together with a propylene copolymer, an ethylenecopolymer or a mixture thereof. Of course, it will be appreciated thatthe above-discussed tie-in layer or intermediate bonding agent layer mayalso be used in elongated members that are not microlayers.

Microlayers are believed to exhibit improved drawing capabilities, whichresults in higher strength or modulus. By using higher draw ratios in asingle or multiple stretch process, higher orientation of the materialmay be achieved, resulting in improved strength and toughness. Themicrolayers also exhibit improved impact resistance which is believed tobe due to the greater dissipation of impact energy available because ofthe larger number of individual layers.

The microlayer teachings herein are not confined strictly to the use ofmicrolayers for the formation of elongated members that are onlyselected from fibres, rods, cords, yarns, tapes, filaments, or straps.Other forms are also possible, particularly films (e.g., oriented filmssuch as biaxially oriented films), such as biaxially orientedpolypropylene (BOPP) films. Microlayer elongated members (and otherelongated members) may also be used in applications that do not requirelarge drawing capabilities or improved impact resistance such as,stretch cling films, geophysical textiles, raffia, woven fabrics, sacks,artificial grass, carpets, packaging strap, or the like. Of course,microlayer elongated members may be used in intermediate forms likeother elongated members described herein, with or without consolidation.Microlayer materials may also be used in combination with otherstructures such as metals, woods, textiles, combinations thereof or thelike.

Exemplary microlayer elongated members comprise at least about 50 wt %(of the overall microlayer structure) of a higher melting point materialcomponent B with the balance a lower melting point material component A,in accordance with the foregoing discussion of components A and B, morepreferably between at least about 60 wt % of component B, and mostpreferably between about 70 and 96 wt % of component B with the balancecomponent A. Preferably, component A comprises polypropylene copolymerin an amount of about 0 to 100 wt %, while propylene-ethylene copolymer(e.g. the previously discussed specialty propylene-ethylene copolymer,such as VERSIFY™ copolymer) may comprise about 5 to 100 wt % ofcomponent A. Component A may also include a non-migratory processing orsurface modification (e.g., friction reduction) agent such as discussedpreviously (e.g., polydimethylsiloxane, a fluoropolymer such as afluoroelastomer or the like) in an amount of about 0 to 4 wt % of thecomponent. Component A may also include other compositions as discussedabove in amounts of about 0 to 8 wt % of the component.

Component B preferably comprises a high stiffness polypropylene (e.g.,random copolymer or in an amount of about 80 to 100 wt % of thecomponent, while also comprising a propylene-ethylene copolymer in anamount up to about 10 wt % of the component. The balance of component Bmay be made up of other compositions as discussed above in amounts up toabout 10 wt % of the component.

To illustrate the above, without limitation, microlayer elongatedmembers having from about 100 to 525 layers or more (alternating betweenlayers consisting essentially of component A, and layers consistingessentially of component B, and optionally including other polymercomponent layers) and made to include from about 5 to about 25 parts byweight of the above discussed component A, and about 95 to 75 parts byweight of the above discussed component B, which is drawn at a drawratio of about 18 to 28 at a draw temperature in excess of 150° C.(e.g., 165° C.). More specific examples are included in the followingtable.

Wt % Wt % Draw ratio at component B component A # of layers >150° C. 928 3 20 92 8 129 20 92 8 129 >22 80 20 129 24 80 20 129 24 > 26 80 20 51324

Resulting microlayer structures are capable of exhibiting a tensilemodulus (per ASTM D-638 or IS0527) at least about 10 GPa, and morespecifically at least 12 GPa (e.g., from 12 to 15 GPa). Draw ratios (fordrawing at a draw temperature in excess of 150° C. (e.g., 165° C.)) inexcess of 18, are possible with these materials, particularly for alamellar polymeric body having at least 4 layers including at least afirst layer that includes a first polymeric material selected from athermoplastic polymer, a thermoplastic co-polymer, or a combinationthereof, and having a thickness less than about 50 microns, and anadjoining second layer of that includes a second polymeric materialselected from a thermoplastic polymer, a thermoplastic co-polymer, or acombination thereof, and having a thickness less than about 50 microns.This is particularly so when wherein the first and second polymericmaterials each layer differs relative to each other in composition,degree of crystallization, molecular orientation, molecular weight, meltrate, peak melting temperature, glass transition peak, temperature ofcrystallization, seal initiation temperature, softening point, molecularweight distribution or any combination thereof (for example, amicrolayer that includes a propylene-based polymer, and anotherdifferent adjoining microloayer).

By way of example, without limitation, one possible two step stretchprocess is also used in microlayer elongated members that containbetween about 3 and 33 layers having ratios of component B to componentA of about 3:1 to about 9:1 (e.g., about 4:1). The first stretch iscompleted at about 65° C. (draw ratio of about 6.5) and the secondstretch step is completed at about 165° C. (draw ratio of about 3).Accordingly, as with other stretch operations herein for elongatedmembers having differing characteristics than that just described, onestretch is performed above the melting point of one layer, but below themelting point of another layer, such as the constrained layer. Ofcourse, it will be appreciated that the stretch temperature may varydepending upon the materials selected for the microlayers. For example,without limitation, it is possible that for an elongated member thatincludes a polyester (e.g., PET), that the drawing temperature may rangefrom about 120° C. to about 250° C. Moreover, it is within the teachingsherein to increase the orientation of at least the higher melting pointmaterial during stretching, such as by increasing the HermansOrientation Function, as measured according to the teachings of Zuo, etal., “In Situ Synchotron SAXS/WAXD Studies on Stretching of IsotacticPolypropylene, Poly. Mat'ls. Sci. & Eng., 93 (2005) 761.n addition,microlayer elongated members that combine polypropylene and PET (i.e.Lighter C88 from Equipolymers) are also made (such as having from about3 to 150 alternating layers, e.g., about 5 to 129 layers). A tie-inlayer such as that including maleic anhydride grafted polypropylene(e.g., POLYBOND 3002 from Crompton) may be employed. The five layermaterial is arranged as such: PP-polybond-PET-polybond-PP with a ratioof 7/3/80/3/7. The 129 layer material is arranged as such:(PP-Polybond-PET-Polybond)n-PP, where n is 32, with the same ratio ofmaterials as in the five layer material. By way of summary, withoutlimitation, the present teachings address the fabrication of microlayerstructures that will typically include at least 4 stacked layers, eachhaving a thickness less than about 50 microns, and each layer differsrelative to its adjoining layer in at least one characteristic selectedfrom composition, degree of crystallization, molecular orientation,molecular weight, melt rate, peak melting temperature, glass transitionpeak, temperature of crystallization, seal initiation temperature,softening point, molecular weight distribution or any combinationthereof. In one approach, the polymer of at least one or possibly eachlayer of the elongated member will be a propylene-based polymer (e.g., apolypropylene homopolymer, such as an isotactic polypropylenehomoploymer). For example, one or more (or even all) of the layers mayemploy polypropylene. It is also possible that the polymer of at leastone layer includes ethylene. The polymers of at least two adjoininglayers may include ethylene (e.g., selected from a propylene-ethylenecopolymer, a linear low density polyethylene, a high densitypolyethylene or any mixture thereof.

A variety of other specific combinations of polyolefinic materials maybe employed for microlayers. For example, without limitation, acoextruded multiple layer assembly may formed that includes a polyolefin(e.g., a polyethylene homopolymer) having a melt index below about 4, amolecular weight distribution of less than about 5 and a peak meltingpoint of at least about 128° C., and a polyolefinic adjoining layer(e.g., a co-polyethylene) that has a peak melting point of less than125° C. The coextruded layers may be subject to at least one stretch ata temperature between about 115 and 141° C. Another specific exampleincludes adjoining microlayers of polypropylenes prepared byZiegler-Natta catalysts, wherein each of the adjoining layersrespectively are a homopolymer, a random copolymer, or alternatinglayers of homopolymer and random copolymer. Yet another possiblecombination contemplates the use of a polypropylene homopolymer layeradjoining a polyethylene homopolymer layer, or optionally including anintermediate layer such as a propylene-ethylene copolymer, a randompolypropylene, an ethylene copolymer, or a mixture thereof. Typically,the polymers of at least two adjoining layers each have a peak meltingtemperature that differ by at least about 5° C.

An additive or other functional material may be employed, such as atie-in layer or an intermediate bonding agent layer between at least twoof the stacked layers. Consistent with the teachings elsewhere herein,the materials may include a non-migratory processing or surfacemodification agent selected from silicones (e.g., dimethylsiloxane), ahalogenated polymer, or a combination disposed on an exposed surface ofat least one of the layers.

Consolidation and Shaping of Intermediate Forms

At a relatively early stage of the processing (particularly before theintermediate form is shaped) it is desirable, but not mandatory in everyinstance, that adjoining structural units are movable relative to eachother. One approach to achieving this is to form the intermediate form,but not subjecting it to a consolidating processing step by whichadjoining structural units will become irreversibly joined together,such as by gluing, melting, fastening or otherwise assembling the units.Void space between units can be filled and the intermediate formdensities. Accordingly, it is particularly beneficial at this point thatthe intermediate form not be consolidated, such as by one or more stepsof heating to one or more temperatures above the melting point of atleast one of the materials in the form to cause the material to melt andfuse, and effectively weld with adjoining units. Such heating may bedone while the intermediate form is constrained or unconstrained.Further, such heating step or steps may be performed with simultaneousapplication of a force to the intermediate form.

By way of example, without limitation, a generally polyolefinicintermediate form (whether including a geophysical textile, a multiplelayer structure (e.g., an A-B-B structure or both) may be consolidatedby one or more steps of applying at least about 50 kN (and morespecifically, greater than about 150 kN (e.g., 350 kN), whilemaintaining the form at one or more temperatures above the melting pointof the exposed surface of the elongated members (e.g., from about 100 toabout 175° C., and more specifically less than about 150° C.) for asufficient period of time (e.g., about 1 to about 5 minutes). Longer orshorter times are also possible (e.g., consolidating at an elevatedtemperature for about 0.25 hour, about 0.5 hour, or even longer thanabout 1 hour).

Resulting intermediate forms may include or consist essentially of asingle layer (which optionally may include one or a plurality ofpatterns). An intermediate form that includes a plurality of layers(which optionally may include one or a plurality of patterns) over someor all of their respective surfaces, is also contemplated. For example,if a plurality of layers is employed, it is possible that one or morelayers are different from each other in one or more respect, such asmaterial type, composition of the elongated member, heat treatment ofthe elongated member, width or other dimension of the elongated member,pattern type, whether the layer is consolidated or not, the presence ofa film layer, thickness, morphology, or any combination thereof. Toillustrate, it is possible that at least one first layer selected from afilm, a coating (e.g., a solvent coating, an extrusion coating orotherwise), a woven form, a winding form, a knit form, a braided form, arandomly dispersed form or any combination thereof adjoins at least onesecond layer selected from a film, a coating (e.g., a solvent coating,an extrusion coating or otherwise), a woven form, a winding form, a knitform, a braided form, a foam form, a randomly dispersed form or anycombination. At least one layer may optionally be a geophysical textileor include microlayers. As indicated, at least one of the first orsecond layers may be consolidated in this illustration.

In instances when the intermediate form is a single layer, as well as ininstances when it is desired to have a plurality of layers as part of anintermediate form, one or more layers may be processed for preventingseparation of individual structural units, the respective layers, orboth. For example, for a single or multi-layer form, one or more of thelayers may be secured (and optionally secured to each other for amulti-layer form) in a suitable manner, such as by thermally joining thestructural units along at least a portion of one, two or more of theedges of the form. Other approaches to processing may be employed, suchas a mechanical step (e.g., crimping, fastening, stapling, riveting,stitching or otherwise), an adhesive joining step (e.g., with a drop orbead of adhesive, a tape or otherwise), or a combination. In this mannerit is possible to readily handle the intermediate forms, such as fortransport, storage, placement in a tool cavity or otherwise, whilereducing the likelihood that individual structural units will becomeseparated to the extent that the intermediate form integrity iscompromised.

Where a plurality of layers are employed in the intermediate form, thenumber of layers can be selected as desired for the intendedapplication. For example, it is possible that more than two, three,four, five or more layers will be employed. Accordingly, it isenvisioned that the intermediate form, in an unconsolidated state mayhave a thickness as small as the thickness of elongated member in it,but may be greater, such as on the order of about 0.25 to about 2.5 cmor larger. In the consolidated state, accordingly, it is envisioned thatthe intermediate form may result in a thickness of about 0.8 mm to about1.5 cm or larger, for example about 0.1 to 0.8 cm or more specificallyabout 0.3 to 0.5 cm).

In another aspect of the present invention, the intermediate form (whichmay include one or a plurality of layers as discussed in the above)optionally is shaped to a desired configuration prior to forming afinished article. This shaping can be performed in a consolidation step(e.g., during thermoforming or other forming under elevated temperatureor hot-stamping), or even in a cold stamping or other operation forinducing local strain hardening, with or without attendantconsolidation. In the course of consolidation, typically, theintermediate form will initially be drapable upon itself. Uponconsolidation, the form will become at least semi-rigid, preferably sothat it is capable of supporting its own weight. It will be typical thatupon shaping and consolidation, the forms of the present invention willbe capable of long term shape retention, e.g., greater than 2 weeks,more specifically greater than one month, and even more specificallygreater than 3 months. In this manner, it is contemplated that a formmanufacturer can generate an inventory of forms, which can then bestored for an extended period until needed for assembly into acomposite.

It will be appreciated that in the course of preparing the intermediateforms of the present invention, the forms may be strain hardened (i.e.,strengthened or hardened by plastic deformation below therecrystallization temperature range of the constituent materials).Strain hardening may occur before, during or after consolidation. Ifafter consolidation, then it is preferred that strain elongation be keptbelow about 15% and more preferably below about 10%. If before or duringconsolidation, the strain elongation amounts can be at least about 10 to40%. Higher or lower amounts are also possible. One particular approachto shaping of the intermediate form (whether single layer ormulti-layer) involves the employment of a resilient structure thatpermits for displacement (e.g., slippage) of the intermediate formduring deformation. Various particular approaches are disclosed, withoutlimitation, co-pending and commonly owned U.S. Provisional ApplicationSer. No. 60/718,025, filed Sep. 16, 2005 (attorney docket 1062-051P1),entitled “Apparatus and Process for Manufacturing Shaped PlasticReinforced Composite Articles,” (incorporated by reference). By way ofexample, it is contemplated that a intermediate form that includes aplurality of thermoplastic elongated members is deformed whiledisplaceably clamping a heated intermediate form during the deforming.The intermediate form is thus clamped in a manner such that while aforce is applied for deforming the intermediate form, the intermediateform is free to move without deformation within a predetermined limit.The thermoplastic elongated members of the intermediate form are atleast partially consolidated for forming a three dimensional articlehaving a predetermined orientation of the elongated members. Optionally,the intermediate form is stamped in a secondary forming operation (e.g.,below the temperature of the displaceably clamping step, such assubstantially at or below room temperature).

Of course, many geometries are possible and contemplated within thepresent invention. Further, the intermediate form need not be amulti-layer form, but can be a single layer. The shaped intermediateform can be further processed as disclosed herein, such as by moldinganother material in intimate contact with the shaped intermediate formto form a reinforced composite material. As can be seen, shapedintermediate forms of the present invention typically will involve athree-dimensional configuration. Moreover, it is contemplated that theshaped intermediate form in most instances will undergo no visuallydetectable size or shape transformation when it is processed to form theresulting composite. However, it may be possible, in accordance with theteachings herein, to strain harden the shaped intermediate form prior,during or after consolidation (e.g., by no more than about 10%elongation).

After formation or shaping, an intermediate form optionally may besubjected to a further heat treatment, coating (e.g., priming) or otherprocessing step as desired for modifying one or more of its properties.Moreover, either or both of the elongated member or an intermediate formproduced from it may optionally be treated for imparting a functionalityto it. For example, it is possible to employ a step of impartingfunctionality by altering the surface energy, the chemistry (e.g., forincreasing cross-linking) or both of the elongated member, theintermediate form or both. A primer (such as a polyolefinic dispersion)may be applied to the surface of an elongated member, an intermediateform or both, as desired.

The intermediate forms of the present invention are suitably processedfor forming a resulting article. Any of a number of different processesmay be employed. For example, before or after consolidation, it may bepossible to assemble the form with a bulk material (e.g., the aforenotedsecond thermoplastic material, which may be any suitable form, such as asheet, a molding, an plate, a tube, etc.) for forming a shaped articlethat is to be reinforced by the material of the intermediate form, whichbulk material is shaped, unshaped or a combination thereof. Any suitableassembly technique may be employed, for example, the intermediate formmay be adhesively bonded to the bulk material, it may be mechanicallyfastened to the bulk material, it may be welded to the bulk material, itmay be impregnated or infiltrated by the bulk material, it may bethermally fused with the bulk material, laminated to the bulk materialor any combination thereof.

The intermediate form may be assembled (in a consolidated, partiallyconsolidated or unconsolidated state) with the bulk material during astep (which may optionally include constraining one or both of the bulkmaterial and the intermediate form) of thermoforming, vacuum forming,pressure forming, compression molding, blow molding, injection molding,rotational molding, hot pressing, laminating (e.g., extrusionlaminating, such as by feeding an intermediate form and a bulk materialthrough a roller, with the intermediate form below and/or above the bulkmaterial), extrusion blow molding, profile extruding, hydroforming orany combination thereof. It is also possible that the intermediate formmay itself include an insert or other member or carrier, whichcombination is together assembled with the bulk material. For example,an extruded profile may be wound with an elongated member, and thecombination then assembled with the bulk material.

One specific example for making a composite pipe, or a structure thatincorporates a composite pipe, involves overmolding, and includes stepsof shaping and consolidating the intermediate form, placing the shapedand consolidated intermediate form into a cavity of a tool, andintroducing a liquefied bulk material into the cavity with theintermediate form, wherein upon solidifying, the resulting articleincludes the solidified bulk material molded onto and reinforced withthe intermediate form. Even more particularly, it is contemplated that ashaped and consolidated intermediate form including a firstthermoplastic material is placed into a cavity of an injection moldingtool, and a second thermoplastic material is molded (e.g., insert moldedor overmolded) by injection molding a bulk material, namely the secondthermoplastic material into the cavity.

The temperature at which the second thermoplastic material is introducedinto the cavity is sufficiently high that it causes at least a portionof the intermediate form to melt and resolidify in intimate bondingcontact with the second thermoplastic material. In this regard, it maybe possible to control the tool temperature into which the secondthermoplastic material is introduced to help control the rate ofsolidification. For example, one approach is to employ a fluid cooledtool, such as a liquid (e.g., water) cooled tool and to maintain thewall temperature of the tool adjacent the cavity at more than about 15°C., more specifically more than about 3° C., below the melting point ofthe lowest melting point of the materials in the intermediate form(e.g., the component A material in an A-B or A-B-A type material).

By more specific way of illustration, for injection molding athermoplastic material (e.g., a polypropylene material) into a toolcavity that has an intermediate form including about 3 to 8 layers of anA-B-A elongated member (e.g., a tape where the component A includes amaterial with a melting point of about 120° C.), a water-cooled tool(e.g., made of a tool steel such as one including chromium andmolybdenum (such as P20), PX5, H13, S7 or the like) is used to maintainthe wall defining the tool cavity at a temperature of about 80° C. Afterinjection molding, for a typical part that has a wall thickness of about2 to 4 mm and an overall weight of about 0.3 to 1 kg, the molded articleis kept in the tool for about 5 to 60 seconds or more prior to ejection.For example, for articles prepared according to the present invention,it is expected that the time will more typically range from about 15 to35 seconds. An example of a suitable molding machine is a 300 metric tonDemag injection molding machine.

In yet another aspect of the present invention, large dimensioned parts(e.g., greater than about 0.5 meter, and more specifically greater thanabout 1 meter, in its largest dimension) are molded to include areinforcement of the intermediate form in a consolidated state (even ifonly as little as about 10% by volume is consolidated). By way ofexample, a reinforced automotive bumper assembly (which may also includeone or more other components such as a bumper beam), or other componentrequiring the use of a large platen tool, may be prepared. In thismanner, many parts can be made by injection molding, which heretoforerequired compression molding for forming a shape.

As indicated previously, the bulk material that is molded with theintermediate form to make a reinforced composite article generally willbe a thermoplastic material. Such material may be unfilled or filled(e.g., with one or more of fibers, microspheres, nanoparticles, orotherwise, such as glass, clay, talc or the like). However, in someembodiments, it is possible that the material will be a thermosetplastic (e.g., a urethane, a rubber, an epoxy or otherwise). While it ispreferred that the bulk material is a thermoplastic that is of the samegenerally type as the thermoplastic in the intermediate form, it neednot be. Materials that can be used for the second thermoplastic materialin the bulk material and/or from which an elongated member may be formedinclude, without limitation, any of the materials that are used in thefirst thermoplastic material of the intermediate form and vice versa.Specific examples include thermoplastic olefins polyolefins, ultra highdensity polyethylene, high density polyethylene, medium densitypolyethylene, low density polyethylene, very low density polyethylene,ultra high density polypropylene, high density polypropylene, mediumdensity polypropylene, low density polypropylene, very low densitypolypropylene, polycarbonate, polyvinylchloride, (meth)acrylonitrile,(meth)acrylate, polyurethane, thermoplastic elastomer, thermoplasticolefin, polyamide (e.g., nylon 6, nylon 6,6 or otherwise), polysulfone,polyester, polyalkylene terephthalate (e.g., poly(ethyleneterephthalate), poly(butylene terephthalate),poly(1,4-cyclohexanedimethanol terephthalate) or otherwise),polyalkylene naphthalate (e.g., poly(ethylene naphthalate)),acrylonitrile butadiene styrene, polyarylene sulfide (e.g., polypheylenesulfide), thermoplastic urethane, PPE, polystyrene, or any combinationthereof (whether in the form of a copolymer, a blend or an alloy). Anyor more of the other polymeric materials described herein may also beemployed.

For example, without limitation, one particular approach contemplatesthat one or both of the bulk material and the elongated member materialare selected from polyolefins, polycarbonates, polystyrenes, vinyls,polyamides, polyalkylene terephthalates, polyesters, polyphenylenesulfides, (meth)acrylates or any combination thereof.

It can be seen that the bulk material may be selected so that it can bemolded in color. Alternatively, it may be coated for achieving a desiredappearance.

Though it is possible that the melting point of the bulk material thatis combined with the intermediate form will be below the lowest meltingpoint of any material in the intermediate form, it is expected that morecommonly the melting point of the bulk material will be above thehighest melting point of any material in the intermediate form. Forexample, it is possible that a difference between the melting point ofthe bulk material and the highest melting point of any material in theintermediate form will exceed 10° C., more specifically 30° C., and evenmore specifically 50° C.

In yet another aspect of the present invention, reinforced compositesmade according to the present invention exhibit excellent dimensionalstability over a broad range of temperatures. For example, the linearcoefficient of thermal expansion (−40° C. to +80° C.) may range fromabout 17 to 24 μm/m-° C., and more particularly is about 19 μm/m-° C.

Following the formation of a shaped composite article, the resultingarticle may be subjected as desired to one or more post-forming orsecondary operations, such as (without limitation) machining, coating,ultrasonic welding, solvent bonding, offset printing, silk screening,hot stamping, engraving, surface treating, bending, pressing, coronadischarging, plasma treating, flame spraying, any combination thereof orotherwise.

It should also be appreciated that, in connection with any shaping orconsolidation step, it is possible that one or more heating steps areemployed for the intermediate form. Such step or any other heating stepin accordance with the present invention may be performed by conduction,convection, radiation or any combination thereof. An oven may be used asa heat source. A radiofrequency heat source, a microwave heat source orboth may also be used. Heating may be done in an inert atmosphere, or inair. Further, heating steps may include a plurality of steps eachperformed at a different temperature, each performed under applicationof a different pressure, or a combination thereof.

With reference to FIG. 3, there is shown an illustrative example of ashaped three dimensional article 100. The article has an upper surface102. Though loose fibers or frayed edges may result at a periphery 104,depending upon processing steps, they may be obviated (e.g., it iscontemplated that they may be removed by a suitable punching, trimmingor other cutting step, or avoid by a suitable step for joining edges ofthe intermediate form. An interior portion of the article 106 may beconsolidated relative to a portion 108 that is not consolidated.illustrated as prepared from a multi-layer drapable form that employs aweave of tape. The loose fibers shown are for illustration, and it iscontemplated that they will be removed by a suitable punching, trimmingor other cutting step.

To the extent not already disclosed other variations of the presentinvention are also contemplated. For example, the elongated members mayconsist essentially of a single type of material (e.g., a thermoplasticsuch as a polyolefin), or it may include a different type of material,such as one selected from glass fiber (e.g., E-glass, S-glass orotherwise), carbon fiber, a metal fiber, a different plastic fiber(e.g., aramid fiber), ceramic fiber (e.g., silicon carbide fiber), anatural fiber, combinations thereof or otherwise. Elongated members maybe coated or uncoated. An intermediate form may be impregnated with asuitable chemical agent, polymer compound, filler or other impregnant.Surface finishes, additional layers or both may be applied tointermediate forms or resulting shaped articles, including for exampleone or more component for reducing static, light stabilization,hydrophilicity, hydrophobicity, fire retardancy, coloring, conductivityor any combination thereof.

As to the foregoing, it will be appreciated that the ability to form anaesthetically pleasing article is another potential benefit of thepresent invention. For example, one embodiment contemplates the use of aplurality of elongated members in an intermediate form of differentwidth, thickness, color, any combination thereof, or otherwise. In thismanner a desired texture, topography, pattern or other characteristiccan be obtained. In addition, the formation of complicated shapes ispossible and is done in accordance with the present invention, such asthe formation of ribs, fillets, corrugations or other protuberances.

It is also possible to employ the intermediate forms of presentinvention in articles that also employ in combination a woven ornon-woven fibrous (e.g., continuous or chopped glass or otherwise) mat.

It is also possible in accordance with the present invention to employan intermediate form as described as a substitute for a plastic film inmultilayered (e.g. laminated) articles.

In addition to the above, it is also possible that a plurality of theelongated members of the present invention can be chopped and randomlyor controllably dispersed within an intermediate form of the presentinvention. Other aspects can be gleaned with reference to U.S. Pat. No.5,872,067, incorporated by reference.

Applications

Articles made in accordance with the present invention exhibit excellentimpact resistance and other mechanical properties. It is contemplated,for example, that automotive vehicle components will meet or exceedstandards for energy management in side impacts, knee bar and glove boxdoor impact, header and rail head impacts and/or bumper performance,such as United States Federal Motor Vehicle Safety Standard (“FMVSS”)214, FMVSS 208, FMVSS 201, and/or otherwise embodied in 49 C.F.R. 581.

Other possible variations can be gleaned by reference to existingliterature such as, without limitation, WO 2004/028803; WO 03/008190; WO98/46422; WO 94/12334; WO 91/11324; U.S. Pat. Nos. 6,710,253; 6,045,923;5,993,711; and EP 1403038A1, all of which are hereby incorporated byreference.

The materials of the present invention are suitable for any of a numberof different applications, ranging from automotive vehicle components,to construction materials, to appliances, and other applications.Examples include, Without limitation, a spare tire well liner, a cargoliner, a bed-liner, a seat back, a vehicle dashboard, vehicle instrumentpanel, a knee bar, a glove box, vehicle interior trim, a bumper, aspoiler, an air diffuser, a hood scoop, an air dam, a fuel tank, a sunroof deflector, a vehicle stone guard, an automotive body panel, avehicle wheel well liner, a shifter knob, a switch knob, a hand-brakebrake handle, a luggage roof box, a door handle, body armor, a helmet, aboat hull, a flotation device, a shipping container, luggage, anattaché, a shin guard, an elbow pad, a knee pad, a chest protector, aface mask, a pipe, a tabletop, a pressure vessel, a protective shield,downhole drilling equipment housing, a boat hull, a safe, a lock, afluid container, a flooring, a wall or other panel, roofing, arefrigerator housing, a washer/dryer housing, benches, seats, rails, ahand tool, a prosthesis, an orthotic, a wheelchair or component thereof,a television housing, audio equipment housing, a portable tool housing,a camera housing, a consumer electronic product housing, an airconditioner compressor housing, a beam, a girder, a fascia, a shutter,shoe soles or otherwise.

In one aspect, the materials of the present invention find particularlyuseful application in the construction of pipes or vessels, particularlypipes or vessels that will be used as a protective covering, will carrya fluid or both. For example, the present invention contemplatesprocesses for making pipes for heavy-duty industrial applications, suchas for transferring chemical reactants or products or channeling, water,sewage or even gas, such pipes being generally rigid or semi-rigid, andoptionally flexible over some or all of its length.

The pipes made using the materials of the present teachings show goodphysical characteristics such improved hoop stress performance, ringstress performance, durability and low temperature impact resistanceperformance, particularly as compared with unreinforced pipes of similarmaterial.

As seen with reference to FIGS. 4A-4D, construction of a pipe 200 inaccordance with the present invention may consist essentially of asingle wall 202, or as in FIG. 4B it may include two or more walls 204and 206 (at least one of them including an intermediate form). Where aplurality of walls are employed, they may be concentric, as in FIG. 4B,or they may comprise a one or more outer walls 208 and one or moreinterior disposed walls 210 (which in turn may be a single or plurallayer construction), such as for defining subdivided pipes, as in FIG.4C. They may be straight or wound over at least a portion of theirlength. The wall structure may include one or more rounded, flat, orcurved sections). Other structures are also possible. FIG. 4Dillustrates an example of one preferred construction in which a jacket212 overlies the structure of FIG. 4B. The jacket may also overlay theembodiments of FIGS. 4A and 4C. The jacket is shown as adjoining theunderlying structure in contact therewith, but it may also be spacedthereform over at least a portion of its interior. It will beappreciated that vessels made herein can include the pipes with at leastone closed end.

The wall 202 defining the pipe of FIG. 4A may generally consistessentially of an intermediate form (particularly one that has beenconsolidated) as described herein in accordance with the presentinvention. For pipes of the type as shown in FIGS. 4B and 4C, at leastone of the wall structures will include an intermediate form accordingto the teachings herein (e.g. prepared from the previously discussedcomponents A and B). The intermediate form commonly will be in aconsolidated state, but it may also be substantially unconsolidated.Portions of the pipes other than that including the intermediate formmay comprise any material suitable for making a pipe, hose or conduitand may be metal, plastic, composite, mono-layer, multi-layer orotherwise made of a suitable material. Preferably the core pipecomprises a polymer (e.g. polyolefin), and more preferably ofpolyethylene, polypropylene or PET. In one aspect, a wall of the pipemay be made of any of the materials discussed herein. For example, thecore pipe may be a extruded member having one or more components (e.g.the previously discussed components A and B). In one specificembodiment, the pipe includes a pressure classified polyethylene with asuitable stabilization package having a suitable pressure rating (e.g.equal to or greater than PE 80 as measured by ISO9080).

As seen in FIG. 4E-G, the elongated member 214 (having a width (w)) ofthe intermediate form may be wrapped or wound (e.g., helically) around acore pipe 216 in a manner suitable for making a hose, vessel or otherpipe structure, and optionally consolidated. In one aspect, multipleelongated members may be braided together to cover the core pipe, whichmay in turn lead to increased durability and low temperature impactresistance of the pipe. Any suitable angle (a) may used for thewinding(s) of the elongated members around the core pipe, with the anglebeing preferably about 30° to 90° relative to the perpendicular axis ofthe pipe. More preferably, the angle of the winding angle is greaterthan about 45°, and more preferably greater than 50° but less than 55°(e.g., about 45° to 54°). In one aspect, for achieving an especiallyattractive combination of axial and hoop stress performance, an angle ofabout 54.7°. However, it should be appreciated that even larger windingangles are desirable if possible, such as greater than about 60° (e.g.,from 60 to 75°), or even greater than about 75°. Any suitableintermediate form may be employed, including windings, weaves or acombination. Consecutive windings may adjoin or overlap each other, orthey may be spaced relative to each other such as by a pitch distance(p), which may range up to about 10, 25 or even about 50 mm or more,such as for a pipe having a diameter (d) of from about 5 to 500 mm, 1000mm or even 2000 mm, and more specifically about 10 mm to 100 mm orlarger. The number of layers of windings may vary for achieving thedesired properties in the resulting pipe. For example, the number ofwinding layers may range from about 1 to 100, or even from about 2 to50. Some embodiments may employ up to about 25 winding layers, and somemay contain as few as about 10 or less winding layers.

In one aspect, the core pipe is covered with multiple layers ofelongated members, such as two, three, four, five or more layers. Thesame or different materials may be used for each layer. In a preferredembodiment, at least two layers of the same materials are used to coverthe core pipe. Each layer is counterwound in the opposite direction atan identical angle to the perpendicular axis enabling a balanced layerstructure. It should be appreciated, of course, that as between eachwinding layer it is possible to vary the winding angle, to vary thecomposition or other characteristic of the elongated member, to vary thewidth or thickness of the elongated member, to apply a film layer, toapply a coating, to vary the pitch distance, or any combination thereof.The step of winding can be performed at room temperature. It may also beperformed at an elevated temperature (e.g., at least about 40° C.

In addition, an optional, but preferred, protective jacket may beincluded on the pipe over some or all of the external surface. Forexample, it will lie over at least a portion of the outermost layer ofthe core pipe/intermediate form assembly. The protective jacket may beany material which increases resistance of the pipe to abrasion,scratching, slitting, chemical exposure, UV light or other types ofdamage and may contain agents that otherwise increase the long termstability of the material. Preferably, the protective jacket comprises apressure classified polyethylene with a suitable pressure rating (e.g.equal to or greater than about PE 80 as measured by ISO9080).

The pipe may be consolidated at any point, and generally thereafter willexhibit a substantial retention of morphology from its initial state inany elongated member portion. For example, the core pipe may beconsolidated before being covered by the jacket (e.g., by conductedheat, convective heat, radiant heat or a combination thereof). In onepreferred approach, the pipe is consolidated after one or more of thelayers cover the pipe core or after the protective jacket covering hasbeen added. In addition, multiple consolidation steps may be utilized,although only one consolidation step is preferred. One advantageousapproach is to apply an intermediate form over a pipe and thenconsolidate the intermediate form (e.g., by conducted heat, convectiveheat, radiant heat, or a combination thereof). Consolidation may takeplace at an elevated temperature (e.g., for a polyolefinic elongatedmember) of about 100 to about 175° C., and more specifically less thanabout 150° C.) for a sufficient period of time (e.g., about 1 to about 5minutes). Longer or shorter times are also possible, e.g., up to about0.25 hour or longer (as taught previously). In the course ofconsolidation, assuming the material of the elongated member of theintermediate form will at least partially melt and fuse to the pipe.Under such approach, it is possible to secure the reinforcement layersfrom the intermediate forms to the underlying pipe without an optionalstep of laser welding or other local heat treatment.

Preferably, the pipes constructed according to this invention meet orexceed the following physical parameters, such as hoop stressperformance of greater than about 10 MPa at 20° C. for 50 years; slowcrack growth (SCG) performance (per test method ISO 13479) of greaterthan at least 500 h, and more particularly greater than 1000 h at 9.2bar at 80° C.; rapid crack growth (RCP) performance (per test method ISO13477) of greater than 10 bar at 0° C.; or a combination of bothcharacteristics

In one exemplary embodiment, a pipe is constructed with an inner pipe(e.g., a thermoplastic inner pipe, such as a polyethylene, apolypropylene or a combination thereof), two exterior layers ofconsolidated coextruded tapes, which initially are applied to the innerpipe as an unconsolidated winding or woven intermediate form. The tapeshave at least an A-B component structure as described elsewhere herein.In one particular example, before applying the tapes to the inner pipe,the tapes will have been drawn to a draw ratio of at least 4, morespecifically at least 8, and even more specifically, at least 12 (e.g.,16). Each layer of coextruded tapes is applied by winding at least oneelongated member at a winding angle of from about 50 to about 600 (e.g.,540). The tapes are consolidated while disposed on the inner pipe byheating at above 150° C. for at least one minute (e.g., at 160° C. forfour minutes), but preferably shorter than about 0.25 hour. Whencompared to the core pipe alone, the exemplary pipe shows at least a 20%and more preferably at least a 30% better burst strength (per testmethod ISO 1167, using a pressure increase of 1 bar min⁻¹ untilfailure). When hoop stress performance (per test method ISO 1167) iscompared (using 80° C. at 7 MPa), the core pipe alone fails in under 10hours, while the exemplary pipe fails only after about 250 hours. Anexemplary pipe made with four layers of coextruded tapes, similar tothat described above exhibits no failures for at least 500 hours, andmore preferably at least about 1000 hours of testing.

As gleaned from the foregoing, the present invention also contemplates amethod of doing business, pursuant to an unconsolidated intermediateform is supplied by a first entity to a second entity in combinationwith delivery of bulk material (e.g., polypropylene). The second entityconsolidates the intermediate form for shaping it and then molds acomposite article with the consolidated form in it. Alternatively, aconsolidated intermediate form is supplied by a first entity to a secondentity in combination with delivery of bulk material. The second entitythen molds a composite article with the consolidated form in it. Thefirst or the second entity may vacuum form, stamp, press, thermoform anarticle with the consolidated form, in addition to or in lieu ofmolding. As can be seen, the first entity may supply the intermediateform in a shaped form, or as a flat sheet. It is also possible that asingle entity makes the intermediate form and the resulting compositearticle incorporating it.

The following examples are not intended as limiting of the presentinvention. It will be appreciated that the relevant teachings thereincan be readily extrapolated by the skilled artisan and used in themanufacture of composite pipes.

EXAMPLE 1

Performance of a consolidated sheet (1.85 mm thickness) of coextrudedtape including an propylene-ethylene copolymer co-extruded with apolypropylene homopolymer as disclosed herein (designated as Sample X)(about 0.04 mm thick by 3 mm wide) is compared with the performance ofmaterials such as that available commercially under the designationCURV™ (denoted respectively as “Sample A” and “Sample B”) in the 1.5 and2.2 mm thicknesses shown), using a falling dart impact test (per ISO7765-1) at room temperature and at (−)40° C. FIGS. 5A and 5B illustratedata obtainable according to a preferred embodiment of the presentinvention.

EXAMPLE 2

A spare tire bin is injection molded with a polypropylene bulk material,along with a three layer (3L) consolidated twill woven coextrudedpolypropylene tape (about 0.04 mm thick by 3 mm wide) intermediate formon one side of the polypropylene bulk material. The resulting article isruck free and exhibits a 400% improvement as compared with a 40% longglass fiber composite with a 20% glass filled polypropylene matrix, whenimpacted at 8 MPH at −30° C. A complete ductile break is observedwithout shattering; i.e., no flying pieces are observed during impact.

EXAMPLE 3

Example 2 is repeated but the intermediate form is placed on both sidesof the polypropylene bulk material, exhibiting enhanced stiffness andimpact resistance relative to the Example 2 composite.

EXAMPLE 4

Example 3 is repeated but with a monolayer polypropylene tape in thetwill weave of the intermediate form. The resulting article is ruck freeand exhibits improvement as compared with a 40% long glass fibercomposite with a 20% glass filled polypropylene matrix, when impacted at8 MPH at −30° C. A complete ductile break is observed withoutshattering.

EXAMPLE 5

A sample of a spare tire bin (2.2 cm deep, 15 cm wide, 25 cm long andwall thickness of 2.25 mm) composite is fabricated from a consolidatedsix layer (6L) intermediate form made with woven coextrudedpolypropylene tape (each layer being about 0.18 mm thick consolidated).The intermediate form is positioned on the bottom of the bin. It isimpact tested and compared with baseline blow molded material a 30%short glass fiber reinforced polypropylene. The test employs an actuatorvelocity of 8 mph, a fixture with a 5.1 cm round impactor. The test isdone at room temperature and at −30° C., and involves hitting the bottomof the bin, off center, with the intermediate form positioned so that itis in tension for receiving the load. The results are shown in thegraphs of FIGS. 6A and 6B.

EXAMPLE 6

By way of illustration of one constrained consolidation operation for amultiple layer woven intermediate form, it is possible that acompression moulding press with manual controls is heated-up to preselected temperature (e.g., from 110 to 150° C.). A woven intermediateform in accordance with the above teachings is cut to the same size asthe plates of the press (e.g., 30×30 cm, with the fabric being cutparallel with the direction of the fibers). Layers of the fabric arestacked up and placed between a protective layer (e.g., a Mylar film),and this stack is placed between a top and a bottom metal plate, whichis delivered to the press. The press is immediately closed, and a forceis applied (e.g., 150 kN is applied for 1 minute). Subsequently, theforce is increased (e.g., to 350 kN for 3 minutes). Press heating isswitched off and open water cooling of the press is performed, while theworkpiece is still under pressure. The press is opened and the platesand Mylar film is removed. The resulting workpiece exhibitsconsolidation (e.g., with a density greater than 95% theoreticaldensity).

EXAMPLE 7

By way of example of one thermoforming operation, a compression mouldingpress (e.g., a manually operated one equipped with a mold for squarecups dimensioned as 20×20×4 cm). Extruded polypropylene sheet islaminated on both sides with a layer of a woven intermediate form (e.g.,by sheet extrusion). The laminated sheet is heated in the press (5minutes contact heat) followed by thermoforming and cooling the pressunder pressure before demoulding. The temperatures of different samplesare varied from 180 to 165 to 150° C. It is observed that delaminationnear the highly stressed and sharp corners becomes lower at the reducedtemperatures.

EXAMPLE 8

A consolidated intermediate form (30×30 cm plate surface) isthermoformed on a manual Fonteyne compression moulding press, equippedwith a square cup mold. The initial forming temperature(T_(male side and female side)) is 150° C. It is heated 5 minutes in thepress, by contact heat. Then the press is closed and for 1 minute aforce of 50 kN is applied. The resulting article exhibits an attractivesurface finish.

EXAMPLE 9

An extruder (operated at a temperature of 165 (drop-in) to 190° C., anda die temperature of 200° C.) is used. Upper, middle, and lower rolltemperatures are respectively 90, 80, and 40° C. A line speed of0.8-0.10 m/min is used. The feed stock has a sheet width of 35 cm, athickness of 1.0 to 1.2 mm polypropylene, and the intermediate forms areeach 0.2 mm thick and 50 cc wide. The intermediate forms are fed at thefirst roll from above, and in a separate run, the intermediate forms arefed at the first roll from below. In yet another run, opposing layers ofthe intermediate form are fed from the top and the bottom at the firstroll. Good adhesion is obtained, with no or insignificant amounts ofwarpage detected.

As can be appreciated from the above, articles made in accordance withthe present invention exhibit a number of beneficial characteristicsincluding, without limitation, recyclability, the ability to reduce wallthickness (and attendant weight and material cost savings) as comparedwith unreinforced materials, good low temperature impact resistance,shatter-free on impact, good long term creep resistance, good long termfatigue resistance, good abrasion resistance, long term dimensionalstability, or any combination thereof.

By way of example, without limitation, as compared with glass filledpolypropylene materials, a self-reinforced composite (e.g.,polypropylene composite) (with a density of about density of 0.8 g/cc)in accordance with the present invention is capable of doubling,tripling or even quadrupling baseline room temperature toughness andlower temperature toughness.

It should be appreciated that in one particular aspect of the presentinvention, many of the foregoing properties are the result of acombination of materials selection and processing conditions that resultin high degrees of retained morphology, for example, the preservation ofsubstantial orientation within the elongated member component of theintermediate form throughout all processing steps until completion ofthe finished article. Specifically, one approach of the presentinvention is to avoid any step of consolidating the intermediate formprior to thermoforming, stamping or other intermediate form shapingstep. Prior materials would employ a consolidation step prior to anysuch intermediate form shaping step. However, such orientation ofpreservation is not mandatory for many of the novel embodimentsdisclosed herein. Accordingly, the skilled artisan will recognize thatvarious of the prior art materials that employ a consolidation stepprior to an intermediate form shaping step may still be employed formaking composites within such embodiments. In addition, it is possiblethat multi-layer intermediate forms may be employed with fewer than allof the layers having been processed for maintaining orientation.

Reference herein to “first” and “second” are not intended as limiting tocombinations that consist of only first and second items. Whereso-referenced, it is possible that the subject matter of the presentinvention may suitably incorporate third, fourth or more items.Reference to “elongated member” is not intended to foreclose coverage ofa plurality of elongated members. Further, reference to “(meth)acrylate”refers to either or both of acrylate and methacrylate. Except wherestated, the use of processing steps such as “consolidating” or “shaping”or their conjugates do not require complete consolidation or shaping; apartial consolidation or shaping is also contemplated. The disclosure ofan “A-B” component structure does not foreclose the presence ofadditional layers, or additional materials that differ from components Aand B. Moreover, the disclosure of “a” or “one” element or step is notintended to foreclose additional elements or steps. Use of the term“about” or “approximately” in advance of a range denotes that both theupper and lower end and not intended as being bound by the amountrecited in the range (e.g., “about 1 to 3” is intended to include “about1 to about 3”). Unless otherwise stated, or as dictated otherwise by thecontext of usage, references to “mixtures” or “combinations” of polymerscontemplates alloys, blends or even co-polymers of such polymers.

Unless stated otherwise, dimensions and geometries of the variousembodiments depicted herein are not intended to be restrictive of theinvention, and other dimensions or geometries are possible. Pluralstructural components step can be provided by a single integratedstructure or step. Alternatively, a single integrated structure stepmight be divided into separate plural components or steps. However, itis also possible that the functions are integrated into a singlecomponent or step. “Comprising”, “having”, and “including” and theirword forms also contemplate the more restrictive terms “consisting of”and “consisting essentially of”.

In addition, while a feature of the present invention may have beendescribed in the context of only one of the illustrated embodiments,such feature may be combined with one or more other features of otherembodiments, for any given application. For example, microlayerelongated members may be incorporated into pipes, pipes may be utilizedin combination with bulk materials and intermediate forms, thermosetmaterials may be included in the elongated members, microlayers may beincluded in elongated members other than coextruded tapes, or materialsmentioned with regard to one component or aspect of the invention mayused in other aspects of the invention. It will also be appreciated fromthe above that the fabrication of the unique structures herein and theoperation thereof also constitute methods in accordance with the presentinvention.

It is understood that the above description is intended to beillustrative and not restrictive. Many embodiments as well as manyapplications besides the examples provided will be apparent to those ofskill in the art upon reading the above description. The scope of theinvention should, therefore, be determined not with reference to theabove description, but should instead be determined with reference tothe appended claims, along with the full scope of equivalents to whichsuch claims are entitled. The disclosures of all articles andreferences, including patent applications and publications, areincorporated by reference for all purposes. The omission in thefollowing claims of any aspect of subject matter that is disclosedherein is not a disclaimer of such subject matter, nor should it beregarded that the inventors did not consider such subject matter to bepart of the disclosed inventive subject matter.

APPENDIX

Without limitation, unless otherwise set forth, the following areexamples of test procedures that are used for realizing the propertiestaught herein and recited in the claims.

Degree of crystallinity is measured by differential scanning calorimetry(DSC) using a Q1000 TA Instrument. In this measurement a small tenmilligram sample of the propylene polymer is sealed into an aluminum DSCpan. The sample is placed into a DSC cell with a 25 cubic centimeter perminute nitrogen purge and cooled to about minus 100° C. A standardthermal history is established for the sample by heating it at 10° C.per minute to 225° C. The sample is kept at 225° C. for 3 minutes toensure complete melting. The sample then is cooled at 10° C. per minuteto about −100° C. The sample is again kept isothermal at −100° C. for 3minutes to stabilize. It is then reheated at 10° C. per minute to 225°C. The observed heat of fusion (ΔH_(observed)) for the second scan overa range of 80-180° C. is recorded. The observed heat of fusion isrelated to the degree of crystallinity in weight percent based on theweight of the sample (e.g., sample of polypropylene) by the followingequation: Crystallinity %=(ΔH_(observed))/(ΔH_(isotactic pp))×100, wherethe heat of fusion for isotactic polypropylene (ΔH_(isotactic pp)) isreported in B. Wunderlich, Macromolecular Physics, Volume 3, CrystalMelting, Academic Press, New York, 1960, p 48, is 165 Joules per gram(J/g) of polymer. The peak temperature of crystallization from the meltis determined by the DSC as above with a cooling rate of 10° C./min. Themelting temperature is determined by the peak of the melting transition.A similar analysis would apply for materials other than polypropylene,substituting reported ΔH values for the other materials.

Molecular weight distribution (MWD) (e.g., for the polypropylenehomopolymers) is determined by gel permeation chromatography (GPC) asfollows. The polymers are analyzed by gel permeation chromatography(GPC) on a Polymer Laboratories PL-GPC-220 high temperaturechromatographic unit equipped with four linear mixed-bed columns,300×7.5 mm (Polymer Laboratories PLgel Mixed A (20-micron particlesize)). The oven temperature is at 160° C. with the autosampler hot zoneat 160° C. and the warm zone at 145° C. The solvent is1,2,4-trichlorobenzene containing 200 ppm 2,6-di-t-butyl-4-methylphenol.The flow rate is 1.0 milliliter/minute and the injection size is 100microliters. A 0.2% by weight solution of the sample is prepared forinjection by dissolving the sample in nitrogen purged1,2,4-trichlorobenzene containing 200 ppm 2,6-di-t-butyl-4-methylphenolfor 2.5 hrs at 160° C. with gentle mixing.

The molecular weight determination is deduced by using ten narrowmolecular weight distribution polystyrene standards (from PolymerLaboratories, EasiCal PS1 ranging from 580-7,500,000 g/mole) inconjunction with their elution volumes. The equivalent molecular weightsfor the sample polymer (e.g., polyproplyne) are determined by usingappropriate Mark-Houwink coefficients (as described by Th. G. Scholte,N. L. J. Meijerink, H. M. Schoffeleers, and A. M. G. Brands, J. Appl.Polym. Sci., 29, 3763-3782 (1984), incorporated herein by reference) andpolystyrene (as described by E. P. Otocka, R. J. Roe, N.Y. Hellman, P.M. Muglia, Macromolecules, 4, 507 (1971) incorporated herein byreference) in the Mark-Houwink equation: {η}=KM^(a), whereK_(pp)=1.90E-04, a_(pp)=0.725 and K_(ps)=1.26 E-04, a_(ps)=0.702, foranalysis of a polypropylene sample.

Unless otherwise indicated, for the materials listed herein, 1% Secantflexural modulus is determined by ASTM D790-00; density is measured perASTM D792; melting temperatures are derived by differential scanningcalorimetry per ISO 11357-3; and flexural modulus is determined per ISO178.

Melt flow rate is measured in accordance with ASTM D 1238-01 test methodat 230° C. with a 2.16 kg weight for the propylene-based polymers. Meltindex for the ethylene-based polymers is measured in accordance withASTM D 1238-01 test method at 190° C. with a 2.16 kg weight.

Xylene solubles are determined by dissolving 4+/−0.1000 g. of sampleinto a 250 ml Erlenmeyer flask and adding by means of a pipette 200 mlof inhibited xylene. To inhibit xylene, add 18.35 g of Irganox 1010 to200 mls. of xylene in a beaker and stir until dissolved. After theIrganox 1010 is dissolved, pour the solution into a 4.9 gallons ofxylene and thoroughly mix the solution. Introduce a stirring bar, placea water-cooled condenser on the flask and position the flask assembly ona magnetic stirrer/hot plate. Stir vigorously and adjust heating toobtain gentle boiling until the sample is completely dissolved. Anitrogen blanket should be maintained on the condenser during theprocedure. After the sample is dissolved, remove the flask assembly fromthe magnetic stirrer/hot plate, remove the stirring bar, then cover. Letthe flask cool to near room temperature (30° C., cooling takesapproximately 1 hour). Place a lead ring on the flask and immerse inconstant temperature water bath. After temperature inside flask reaches25+/−0.5° C., let stand in water 30 more minutes. During the cooling,the insoluble portion precipitates. The solution is filtered; then a 100ml aliquot of the filtrate is placed in an aluminum pan and evaporatedto dryness under a nitrogen stream. The solubles present are determinedby weighing the residual polymer.

Isotactic pentad percent, Isotactic triad percent and the Isotacticpentad/triad ratio are determined by one of ordinary skill in the artaccording to the following: ¹³C nuclear magnetic resonance (NMR)provides a direct measure of the tacticity of poly(propylene)homopolymers. The analysis used here neglects chain ends and inverseinsertions. For the triad names (m, mr, and rr) ‘m’ stands for meso, and‘r’ stands for racemic. The isotactic triad percent is a measure of themm triads. V. Busico, R. Cipullo, G. Monaco, M. Vacatello, A. L. Segre,Macromolecules 1997, 30, 6251-6263 describes methods for determiningisotactic pentad and triads using NMR analysis.

The isotactic pentad/triad ratio is the ratio of the isotactic pentadpercent to the isotactic triad percent. In determining the isotacticpentad and triad values, the samples are prepared by dissolving 0.5 g ofthe polypropylene homopolymer in a mixture of 1.75 g oftetrachloroethane-d2 (TCE-d2) and 1.75 g of 1,2-orthodichlorobenzene.Samples are homogenized in a heating block at 150° C. and heated with aheat gun to facilitate mixing. NMR experiments are performed on a VarianUnity+400 MHz, at 120° C., using a 1.32 sec acquisition time, 0.7 secrepetition delay, 4000 acquisitions and continuous proton decoupling(fm-fm modulation), with and without spinning the sample. Total scantime used is 2.25 hrs.

1. A method for making a composite pipe, comprising the steps of:providing a core pipe, covering the core pipe with an intermediate form,heating the intermediate form, and optionally applying a jacket over atleast a portion of the intermediate form and the core pipe forprotecting the core pipe with the intermediate form, characterized inthat: the intermediate form includes at least one winding of at leastone coextruded thermoplastic elongated member, wherein the elongatedmember comprises a first polyolefin material coextruded with a secondpolyolefin material that is different from the first polyolefin andincludes an isotactic polypropylene homopolymer with a peak meltingtemperature greater than 160° C.; and the heating step includes heatingthe elongated member to one or more temperatures above the melting pointof the first polyolefin material but below the peak melting temperatureof the second polyolefin material for consolidating the intermediateform and for at least partially melting the at least one elongatedmember of the intermediate form for fusing the elongated member to thecore pipe.
 2. The method of claim 1, wherein the core pipe comprises apolymer.
 3. The method of claim 1, wherein the intermediate formincludes a plurality of elongated member layers, with at least one ofthe layers including an elongated member stretched to at least 5×. 4.The method of claim 3, wherein the at least one elongated membercomprises a multilayer coextruded tape and the consolidating stepincludes maintaining the intermediate form at a temperature of at least150° C. for at least one minute, after the core pipe is covered with theintermediate form.
 5. The method of claim 4, wherein the intermediateform includes at least two layers of windings.
 6. The method of claim 5,wherein the protective jacket comprises a polymer.
 7. The method ofclaim 4, wherein the resulting pipe has a hoop stress performance ofwithstanding a pressure of 7 MPa at 80° C. for up to 250 hours.
 8. Themethod of claim 1, wherein at least one of the polyolefin material ofthe intermediate form, or both includes a non-migratory process aid orsurface modifier agent.
 9. The method of claim 8, wherein thenon-migratory process aid or surface modifier agent includes a highmolecular weight silicone.
 10. The method of claim 9, wherein thenon-migratory process aid or surface modifier agent includes adimethylsiloxane.
 11. The method of claim 1, wherein, at least one ofthe first polyolefin material and the second polyolefin materialincludes ethylene.
 12. The method of claim 9, wherein (i) the firstpolyolefin material comprises a propylene-ethylene copolymer, (ii) thesecond polyolefin material comprises an isotactic polypropylenehomopolymer having a crystallinity of at least 70%, and an isotacticpentad/triad ratio of greater than 85%; or a combination of (i) and(ii).
 13. The method of claim 12, wherein (i) the first polyolefinmaterial has the following characteristics: exhibits a melt flow rate at230° C. per ASTM D1238 of 0.3 to 50 g/10 min; a density per ASTM D792 of0.858 to 0.888 g/cc; an ethylene content of 5 to 25 wt %; a MeltingRange from 50 to 135° C.; a Shore A Hardness from 50 to 75; and aflexural modulus per ISO 178 of 10 to 280 MPa; wherein (ii) the secondpolyolefin material comprises a polypropylene homopolymer that exhibitsa melt flow rate at 230° C. per ASTM D1238 of less than 7 g/10 min; a 1%secant flexural modulus of greater than 2000 MPa; a crystallinity of atleast 70%; an isotactic pentad/triad ratio of greater than 85%; and acrystallization temperature of greater than 133° C.; or a combination of(i) and (ii).
 14. The method of claim 1, wherein the at least oneelongated member comprises a plurality of microlayers.
 15. The method ofclaim 1, wherein the jacket is made of a thermoplastic.
 16. The methodof claim 1, wherein the step of consolidating the intermediate formoccurs prior to application of the jacket over at least a portion of theintermediate form and the core pipe.
 17. The method of claim 1, whereinthe covering step includes winding at least four winding layers on thecore pipe.
 18. The method of claim 1, wherein the step of consolidatingtakes place at a temperature of above 150° C. for 1 to 15 minutes. 19.The method of claim 1, wherein the step of consolidating occurs fromheat realized during the step of applying the jacket.
 20. The method ofclaim 1, wherein the pipe has at least one closed end. 21-23. (canceled)